Tascam 388 Story...

minminmusic

New member
388 Screw Question

Tried on the main board but since this is the Tibetan Monastery of Tascam 388 information figured I'd try here as well.

Looking to find replacement screws and washers for the Side Wood Panels.

It looks like they are metric 4mm X0.40 Thread. Length 25mm with a circular head of 12mm? That's the part I'm iffy on as there are some recessed nylon washers out there but trying to sus out the head size of the screw has been a challenge. Any help amongst the believers would be a blessing! :)
 

sweetbeats

Reel deep thoughts...
You had some other questions about the screws you asked in a new thread to which I responded. I asked there how many do you need? Did you see my reply?

How many do you need? :)

I probably have a couple, but they are probably pretty roached...but I could measure them at least.
 

backbreaker

New member
New to this machine - starter's tips?

Hello,

I am upgrading from the cassette tascams that I am used to and have just purchased on of these. looking for tips and such? where to purchase tapes (using LPR35 RTM PYRAL RMG RMGI- which the machine has been calibrated to). Thanks ahead of time...also any online resources to be directed towards.

Thanks!
 

sweetbeats

Reel deep thoughts...
I replied to you other thread.

I’m working on the issue with the pics. They should still all be there, so I’m trying to nail down where the break is that’s preventing them from displaying.
 

Gman57

New member
Newbie to this forum so please forgive it this is not relevant to this forum. Should this be happening. I have a stereo reverb unit patched through the effects send/receive. Each gain knob plus the master set at 3:00 I have a guitar on track 1. None of the assign buttons (1-8 or L/R) are depressed, track fader at 8, as I raise track 1 effect send I can hear the reverb effect through the stereo outs and headphones. Is this bleed through something that shouldn’t be happening?
 

sweetbeats

Reel deep thoughts...
Welcome!

Normally it is best to start your own thread rather than piggy-back on somebody else’s unless your topic is directly related to the thread your posting on. But let’s get your question answered.

You didn’t specify but I’m going to assume you are talking about a reverb box connected to a 388, yes?

Yes that behavior is normal. If you read up on the EFF buss on the 388, or look at the block diagram, the source of the EFF send pot on the input strips of the 388 is the point after the channel fader and before the PAN control and buss assign switches. You don’t have to have a channel assigned to any of the busses (L-R or PGM groups 1-8) to send signal to the EFF buss, but you do have to have the channel fader raised.

Does that help?
 

Gaspardeden

New member
hi @sweetbeats !

Came upon your thread on the tascam 388 you did a couple of years ago. Went basically through a similar procedure as you did. I completely cleaned, recapped the beast and went through many adjustments and a lot of maintenance.

Everything is up to specs, motors are good, tension arms, pinch roller, everything is adjusted according to the manual using all the equipment required, all functions works perfectly well.

I also want to mention in the first place that I use LPR90 tape which is basically the same thing as LPR35 only slightly thicker.

We adjusted the heads too (azimuth and tilt) and had a good reading on the scope.

Problem #1 I wanted to address with you is that track 1 and eight kind of fluctuates on playback (and probably rec), like if the tape path was not perfectly aligned with the heads. It could be best described in the following situation: when I play 400 hrtz on my calibration tape, the vu meter on channel 1 and 8 dances from left to right a little bit; I suspect the azimuth here, or the tilt. Maybe head screws are not tight enough. I wanted your opinion on that; yes we did unscrew both screws on the head to follow the procedure in the manual. My only hope is that it is not a problem that will require to relap the rec repro head.


The second problem:

We did bias calibration up to specs described in the manual. When came the time to adjust the rec EQ we found out we were out of specs; we used a RTA machine, recording a white noise and then analyzing the results on playback.. On track 2, 3 and 4 we have a major drop in high end, and a 60 hrtz bump on every channel (which I think is normal) but to come back to high end loss, we start losing High end from 2k and then around 8k high end is almost completely gone.. this is on channel 3. The 2 others are not as worse but still VERY dark.

Now when I came upon this thread I read the part where you described your operation regarding bias calibration.

You mentioned that bias needs to be calibrated differently from the manual when LPR35 is used.

Would this be the culprit to my high end loss?

Now when you mentioned 120mv for LPR35 where you talking about REC BIAS?

What was your best results for REPRO BIAS? They mention 230 mV for being in specs in the manual.

I am so close to the ending line, it took me one year of heavy researches and finesse to bring my tascam back to life.

Any help from you would be more than welcome.

Thank you!
 

sweetbeats

Reel deep thoughts...
Hi.

So I don’t know what the ideal bias level is for LPR90. It will be different than LPR35, and if it was me I’d be using the LPR35…not because of the bias issue. One of the things that’s problematic or finicky about a 388 is since the R/P heads don’t have edge slots (narrow slots cut above track 8 and below track 1), as a wear path is established, the edges of the tape can curl at the top or bottom of the wear path. And by “curl” I mean ever so slightly lift. This is greatly exacerbated if the wear path was established by the factory specified Ampex/Quantegy 457. Ampex/Quantegy tape slitting equipment was not as precise as pretty much every other tape manufacturer at the time. The tape slitting accuracy was, IIRC, 0.001~0.003” off of the specified tape width. To avoid tape being slightly too wide and causing problems they slightly undersized the width. Again we’re talking a couple thousands of an inch. But what results then with a tape path established by Ampex/Quantegy tape, when you run properly slitted tape, it is slightly too wide in the path…usually one edge curls or slightly lifts. On a super narrow format machine like a 388 the result is signal and fidelity loss on track 1 or track 8, and also issues with edge shed getting on the head. It takes almost nothing as far as debris or edge lift to cause, at times, almost complete loss of signal during record or playback. If there are edge slots that eliminates the sides of the wear trough and now slight variations in tape width don’t matter. Edge shed can still be a problem though at other points in the tape path. The thicker more stiff LPR90 will exacerbate this condition if this is at least part of what you are dealing with. The solution is a relap, unless the wear path is slight. In that case sometimes you can fast-wind through a reel of tape a couple times with the lifters defeated to try and abate the edge lift…try and wear down the path at the edges.

Regarding the bias, again, I don’t know what the bias requirement is for LPR90, you’ll have to determine that by going through the painful process I did, or just take a stab at it. It sounds though like an overbias condition you have there though. With too little bias the distortion level is too high, and as you crest the sweet spot with the bias level the HF performance drops.

When you said you adjusted the azimuth and head “tilt” what did you mean? Usually that’s a euphemism for zenith, but the zenith is fixed on a 388. So did you adjust the wrap angle? I would never, ever do this on a machine with an already-established wear path, because if you change the wrap angle the tape can no longer properly contact the face of the head, even if it was off originally…you’ll go from non-ideal to worse. If what I’m saying doesn’t make sense I’m happy to explain it in other terms. But this goes for rotating fixed guides too. You never ever do that unless it is at the time of a relap and optical setup of the heads and guides in the headblock assembly.

So I know I’m not necessarily a ray of sunshine here, but let me know what follow-up questions you have and maybe try and post some pictures of your R/P head and tape path.
 

Gaspardeden

New member
Hi.

So I don’t know what the ideal bias level is for LPR90. It will be different than LPR35, and if it was me I’d be using the LPR35…not because of the bias issue. One of the things that’s problematic or finicky about a 388 is since the R/P heads don’t have edge slots (narrow slots cut above track 8 and below track 1), as a wear path is established, the edges of the tape can curl at the top or bottom of the wear path. And by “curl” I mean ever so slightly lift. This is greatly exacerbated if the wear path was established by the factory specified Ampex/Quantegy 457. Ampex/Quantegy tape slitting equipment was not as precise as pretty much every other tape manufacturer at the time. The tape slitting accuracy was, IIRC, 0.001~0.003” off of the specified tape width. To avoid tape being slightly too wide and causing problems they slightly undersized the width. Again we’re talking a couple thousands of an inch. But what results then with a tape path established by Ampex/Quantegy tape, when you run properly slitted tape, it is slightly too wide in the path…usually one edge curls or slightly lifts. On a super narrow format machine like a 388 the result is signal and fidelity loss on track 1 or track 8, and also issues with edge shed getting on the head. It takes almost nothing as far as debris or edge lift to cause, at times, almost complete loss of signal during record or playback. If there are edge slots that eliminates the sides of the wear trough and now slight variations in tape width don’t matter. Edge shed can still be a problem though at other points in the tape path. The thicker more stiff LPR90 will exacerbate this condition if this is at least part of what you are dealing with. The solution is a relap, unless the wear path is slight. In that case sometimes you can fast-wind through a reel of tape a couple times with the lifters defeated to try and abate the edge lift…try and wear down the path at the edges.

Regarding the bias, again, I don’t know what the bias requirement is for LPR90, you’ll have to determine that by going through the painful process I did, or just take a stab at it. It sounds though like an overbias condition you have there though. With too little bias the distortion level is too high, and as you crest the sweet spot with the bias level the HF performance drops.

When you said you adjusted the azimuth and head “tilt” what did you mean? Usually that’s a euphemism for zenith, but the zenith is fixed on a 388. So did you adjust the wrap angle? I would never, ever do this on a machine with an already-established wear path, because if you change the wrap angle the tape can no longer properly contact the face of the head, even if it was off originally…you’ll go from non-ideal to worse. If what I’m saying doesn’t make sense I’m happy to explain it in other terms. But this goes for rotating fixed guides too. You never ever do that unless it is at the time of a relap and optical setup of the heads and guides in the headblock assembly.

So I know I’m not necessarily a ray of sunshine here, but let me know what follow-up questions you have and maybe try and post some pictures of your R/P head and tape path.
hi,

Thank you so much for your fast reply.


So yes, to be a little more clear, we did follow the procedure in the manual to adjust the TANGENCY adjustment screws. Sorry about the "tilt" term which is actually not the proper term. As the manual says:

"Slightly loosen the mounting screws which hold record/reproduce head in place and adjust the tangency using adjustment screw,
for maximum output. When the maximum output is attained, retighten both mounting screws."

Thats what we did.

Here are a picture of the screws circled in red. We did retightened them. Let’s hope we did not do something horribly wrong like you mentioned in your previous message.


Now, for the use of LPR 90, I leave a link here with the specs of the tape:


Maybe you would be better suited than me to find out if it matches ampex / quantegy tape from back then.

Many people told me that LPR 90 worked just fine with tascam 388, thst it was basically the exact same thing than LPR35 but only a little more robust, but then you adressed a very interesting issue regarding edge shed getting on the head. Maybe it’s the problem. I would leave a video of how the vu meter of channel 1 behaves when played a 400 hrtz frequency from my nagravox calibration tape but the website doesnt take videos. It basically bounces from one side to the other with fluctuations around -1 and +1 dbs

There is also a distinct sound to it. A little crackling, like the channel is "choking" on something. It’s not extremely audible or problematic, but it’s just there.

Here is also the best pictures I could take of my R/P head and tape path.


Also I need to learn more about biasing. I feel limited and can’t seem to make the right procedure to adapt the machine from a certain type of tape to another; I had this preconceived idea that the manual was going to dictate me exactly what to do and that everything would work correctly.

I went through hell with this machine, learned electronics by trial and errors, made it worse and then better, never gave up on it. I’m certainly not gonna give up now

I’ll be waiting for your response, if you can enlighten me in any way with the infos and material I just shared with you would be more than welcome.

Thank you for sharing your time and knowledge with me.

Kind regards
 

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sweetbeats

Reel deep thoughts...
So yes, to be a little more clear, we did follow the procedure in the manual to adjust the TANGENCY adjustment screws. Sorry about the "tilt" term which is actually not the proper term. As the manual says:



"Slightly loosen the mounting screws which hold record/reproduce head in place and adjust the tangency using adjustment screw,

for maximum output. When the maximum output is attained, retighten both mounting screws."



Thats what we did.



Okay. Well let me ask you this…did the overall output increase after the adjustment from where it was prior to adjusting? If it did, that’s not a bad thing, but that means the head is now in a different position than it was, and you’re starting a new wear path, not just in the heads you adjusted (if you did both R/P and erase heads), but on the guides as well. This is not ideal, but what’s done is done. I’m always super hesitant to adjust heads except for azimuth once there is a noticeable wear path, which yours definitely has. It doesn’t look like a high mileage machine or anything…I’d call it lower than average miles so that’s good. But I wouldn’t mess with any adjustments except for azimuth at this point unless absolutely necessary, and at some point I’d replace the screws if you do have to loosen them…and make sure your driver bit is in good shape. The heads of the fasteners look pretty chewed up.



Now, for the use of LPR 90, I leave a link here with the specs of the tape:



https://static1.squarespace.com/sta...598576/1660032190137/fiche_lpr90_rtm_2022.pdf



Maybe you would be better suited than me to find out if it matches ampex / quantegy tape from back then.



It’s really difficult if not impossible, at least for me, to tell what bias level will be required by a specific machine based on a spec sheet for the tape. The 457 the 388 was specified to use is in the same “class” as LPR35, a “+6 1mil” tape, but according to the gurus at Teac Analog Support in Montebello, CA (back when that existed), and my own experience, the LPR35 needs about half the bias level. I don’t know much about LPR90. But regardless just because two tape types are in the same “class” does not in any way mean they will require the same bias level. And even two different batches of LPR35, or any tape, will need slightly different bias levels. To determine the correct bias level for your machine with tape X you need to do the common overbias method, or the LF modulation “bias rocks” method, or something else…all of which is a PITA with a two-head machine.



Many people told me that LPR 90 worked just fine with tascam 388, thst it was basically the exact same thing than LPR35 but only a little more robust…



Of course it works “fine”, but it will have its own bias requirement, and the thicker or more stiff tape stock will have *some* impact on wear and performance…tape-to-head contact unless tensions are re-set, etc. Always…always, always, always if you deviate from the manufacturer’s specification, there are other factors to adjust. I’m not discouraging the deviation, I’m just saying be prepared to know and understand what all the deviation will impact and what to do about it.



…but then you adressed a very interesting issue regarding edge shed getting on the head. Maybe it’s the problem. I would leave a video of how the vu meter of channel 1 behaves when played a 400 hrtz frequency from my nagravox calibration tape but the website doesnt take videos. It basically bounces from one side to the other with fluctuations around -1 and +1 dbs



+/-1dB fluctuation on an edge track of a narrow format machine….Not unheard of. Now at 400Hz I wouldn’t be happy with that either. 10kHz I’d let it go. But I looked closely at your pictures. You have some issues there that long pre-dated you owning the machine I think. I don’t know if the pics showing the tape in the tape path are with the transport in motion, but it’s blatantly clear from the pics either the tape path of the headblock assembly is too high, or something is pulling the tape down. I can see the wear path is not centered on the erase or R/P head, the tape is curled at the bottom going through the wear path on the R/P head, and my goodness the wear at the bottom of the guide downstream of the R/P head…that’s not right. Again, either the headblock is too high, or the tape path downstream and or upstream of the headblock is too low. Do all of your rollers have the correct thrust washers in place? Look at your service manual at the exploded views and make certain all the washers are in place. Get a bright light and with the machine off manually push the pinch roller up to the capstan shaft and shine the light through between the capstan and pinch roller…does it contact at the top and not the bottom or vice versa? The vertical axis of the two should be absolutely parallel. Is the tension too high? You’ve got to figure that out first. Also while it’s playing shine that light down along the tape…you’ll be able to see the tape buckling.



There is also a distinct sound to it. A little crackling, like the channel is "choking" on something. It’s not extremely audible or problematic, but it’s just there.



Okay that brings up another question: what make model demagnetizer do you have and when did you last degauss the entire tape path?
 

Gaspardeden

New member
Hi @sweetbeats

Sorry for being silent for a couple of days. I’ve been rethinking, troubleshooting and logically approaching the calibration procedure with very good results; I can say today I am proud of myself. I have to thank you on your writings about your bias procedure. It helped me a lot.

Problems I had are now resolved and here is how I proceeded:

- I adjusted the azimuth all over again. I tried my best to get the best result on the oscilloscope. It helped a lot with edge tracks (1 and 8) fluctuation up to a point where it’s almost gone. I can live with that; I’d even say it’s normal on a deck like this one.

- I also did the playback calibration all over again. I realized I did a stupid mistake; I had the wrong cycle on my AC voltmeter.. it was on -10 db mode so everytime I was adjusting trim pots to have a -10 db on the voltmeter I was getting -20 in reality. If you are curious, I use nagravox calibration tape, an australian brand, which is suited for LPR 90. I then adjusted to have the best EQ linearity through each channels and was pretty convinced by the results. Playback was indeed not loud enough which accentuated the print through problem that I finally adressed and resolved through the recording calibration.

-Finally I went through the recording calibration again. I found out I had a major bump around 10k on most of my channels. I tried to adjust that with the EQ rec trim pots but alas it was not ameliorating the situation so I took my courage and started messing around with the Bias of one channel…I started by measuring the voltage of the bias I was working on through the test point and noted it. I then recorded a 40 hrtz frequency, 400, 1000, 10k, 12k, 14k at -10db.. everything is OK up until 10k which as I said before had a major bump.. So I went through your procedure. I did a couple of adjustments on the bias coil. Recorded the frequencies. Played back and measured it. Then did it again. I wanted to notice hoe they were behaving as I was playing with the screw on the bias and get closer to a linear result. And then it happened. At some point I could CLEARLY hear the "waterfall" sound in the low end as you described it.. this is when I had the best linearity with my high frequencies, no bump whatsoever.. So my goal was to get less and less "waterfall" sound to get a cleaner low end but without bumping the high frequencies… this is a really narrow window but I finally found the right formula. I had a super good linear response which was considered in specs with the manual; nothing under 3 or over 3 dbs in fluctuation. Victory! I did it for every channels and then recorded a vocal test. I was amazed by how there was almost no differences between my input signal and my playback signal. How gratifying that was!

But how horrible it turned out!

Another problem pops up! The cherry on the sundae!

I move my tascam 388 back to my studio which I’m setting up at the time, put it on its stand where its supposed to finally rest and be ready to use.

I turn it on, plug a microphone on one of the channels..

No sound (not signal) on the right side. Gosh. What’s happening! I pop the bottom pannel and gently play around with connectors. Right side come back. But then what happens is really strange and this is my problem at the moment.

I have an intermittent problem. Its either I get signal in my channel vu meters but no sound and no signal in the stereo vu meters OR I get sound and stereo meters works but no channel vu meters will move. And this is my (poor) troubleshooting so far:

When I gently tap the M buss pcb, I can clearly see / hear that there’s an intermittent problem somewhere around P910 which connects to P102 on the buss B pcb; this is where the switch happens, either sound but no meters or no sound but meters working. I also suspect the connector J105 just next to P102 that when I play with the cables it makes the sound appear and disappears but I can’t tell if it’s the culprit or not or even if it’s another part of the problem since it’s so close to P102. I can visually notice micro sparks on pin 1 and 2 of P102 when I gently move the m buss pcb from one side to the other (I’m not moving anything crazy, I’m always being very gentle)

To note: I did a full recapping of the tascam 388. Maybe it’s a bad soldering somewhere, maybe not. I scavenged buss b pcb for a bad solder but did not find any.

I’m having trouble reading the schematics and retracing where this problem could come from. I am not used to reading schematics, it’s still a bit abstract for me.

I also don’t know how to probe a connector in circuit to determine if it’s good or faulty.


Any assistance coming from you will be really appreciated. I thought I finally won the war on the 388 but there is, alas, one final battle (let’s hope) before it is over.

Sorry for writing a novel, I had a lot to say. There’s never any short answers in that kind lf business.

looking forward to hear from you
 

sweetbeats

Reel deep thoughts...
Read your whole post.

First of all nice work on the calibration and bias setting. It’s super tedious on the 388 because it’s a two head machine and such a narrow format. But based on your narrative I think you got it. Yes it is a very narrow “tipping point” where you transition from minimal distortion to increased HF response. There’s a narrow “sweet-spot” but it is clear to me you understand this and identified what to listen for and I think that is impressive. Again, harder to do on a machine like the 388, so kudos.

When you setup the 388 properly it does sound very nice. It has this lore for being cool lo-fi, but I think that’s coming from people that don’t know how to properly set it up. And the one I had many years ago that is the subject of this thread, refurbished, recapped, properly setup including bias for the LPR35 tape I was using, it sounded really nice. I think that’s where you’re at. If somebody wants to go lo-fi you can always achieve that through how you setup the front-end and handle post production, but the tape machine shouldn’t, isn’t and doesn’t have to be the limiting factor.

Regarding your new challenges I will, as soon as I can, take your good notes and compare to the schematics and follow up with, likely, some combination of advice, comments and follow up questions. I have some critical family events happening at the moment so it may be some days before I can follow up, but I’m reasonably confident we can get it fixed.
 

sweetbeats

Reel deep thoughts...
So here’s what I would do…P105 is not your problem. It connects only to the BUSS IN jacks. P102, however, is the connector that provides logic and audio power to the BUSS B PCB as well as ground and the AUX and EFF signal. If there is a problem with faulty connections or solder joints there you could have issues with intermittent audio and other odd switching issues because the logic power is there, and there is a logic chip on the BUSS B PCB that manages automatic source switching involving the stereo buss. You say you “scavenged” the board for bad solder joints but you’re not going to be able to tell by looking, even under magnification. If you have little sparks with manipulation at P102 on pin 1, that’s the +5V power rail. It shouldn’t be doing that. Ever. So if it was me I’d start by reflowing the solder joints both on the M BUSS PCB and on the BUSS B PCB associated with P102. Do that and then report back what issues remain.
 

Gaspardeden

New member
O
So here’s what I would do…P105 is not your problem. It connects only to the BUSS IN jacks. P102, however, is the connector that provides logic and audio power to the BUSS B PCB as well as ground and the AUX and EFF signal. If there is a problem with faulty connections or solder joints there you could have issues with intermittent audio and other odd switching issues because the logic power is there, and there is a logic chip on the BUSS B PCB that manages automatic source switching involving the stereo buss. You say you “scavenged” the board for bad solder joints but you’re not going to be able to tell by looking, even under magnification. If you have little sparks with manipulation at P102 on pin 1, that’s the +5V power rail. It shouldn’t be doing that. Ever. So if it was me I’d start by reflowing the solder joints both on the M BUSS PCB and on the BUSS B PCB associated with P102. Do that and then report back what issues remain.
Hey!

Thanks for your message and for cheering me up on the whole bias / calibration thing. It’s really nice to feel validated on this matter.

Ok so I reflowed the solder joints on P102 and P905 and I replugged everything.
There is no more intermittence between the two problems if I manipulate the m buss pcb. It stays on the channel vu meters working but nothing moves on the stereo vu meters and no sound coming out of the speakers. There is also no more sparks on the pins 1 and 2 of P102

I suspect that pin 1 (+5V) soldering joint was half broken.

No matter where I gently tap, I can’t get any sound or stereo vu meter movement so it’s hard for me to identify the source of the problem

Over to you
 

sweetbeats

Reel deep thoughts...
When you say you “can’t get any sound”, be specific as to where there is no sound.

I’m assuming you mean no sound when monitoring the STEREO buss, correct? Is this true at the STEREO OUT jacks as well as in the headphones when the monitor select switch above the headphones level knob is set to STEREO?

Do the STEREO meters function when you set them to monitor the AUX and EFF busses?

What happens if you connect a source to the STEREO BUSS IN jacks? Is there activity on the STEREO meters and signal at the STEREO OUT jacks or in the headphones when the monitor source is set to STEREO? Try this test both with one or more L-R assign switches latched or in the down position on one or more input channels, and also with all L-R assign switches in the unlatched or up position.

What we are doing here is, using the Block Diagram and the 388’s own features and functions, learning as much as we can about where the problem originates before we drill down to the schematic level or do any tracing of the problem. I’m not surprised your repair of the solder joints didn’t fix everything, but good job tackling part of the issue. The description of the problem(s) sounded like compound issues to me, and I have a hunch I know what the problem is, but if you can execute the above tests and answer the questions it will help.
 

Gaspardeden

New member
When you say you “can’t get any sound”, be specific as to where there is no sound.

I’m assuming you mean no sound when monitoring the STEREO buss, correct? Is this true at the STEREO OUT jacks as well as in the headphones when the monitor select switch above the headphones level knob is set to STEREO?

Do the STEREO meters function when you set them to monitor the AUX and EFF busses?

What happens if you connect a source to the STEREO BUSS IN jacks? Is there activity on the STEREO meters and signal at the STEREO OUT jacks or in the headphones when the monitor source is set to STEREO? Try this test both with one or more L-R assign switches latched or in the down position on one or more input channels, and also with all L-R assign switches in the unlatched or up position.

What we are doing here is, using the Block Diagram and the 388’s own features and functions, learning as much as we can about where the problem originates before we drill down to the schematic level or do any tracing of the problem. I’m not surprised your repair of the solder joints didn’t fix everything, but good job tackling part of the issue. The description of the problem(s) sounded like compound issues to me, and I have a hunch I know what the problem is, but if you can execute the above tests and answer the questions it will help.
Hi!

So I did what you asked.

I have sound (signal) in my headphones when I monitor through AUX or EFFECT (switches above the headphones level knob) AND the STEREO vu meter responds. Also I have sound in my speakers when I plug them through the aux out and/or effect out. Everything is working properly there.

Also did the test with feeding a signal through the stereo buss in and it works. I got sound AND the STEREO vu meters are responding.

Over to you!
 
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