Reel to Reel Machine - Head, Lifters, Rollers, Technical Issues?

[horeq]

Hi All,

I would like to know if anyone knows the following. I have a Tascam 52 DB Reel to Reel Machine. There are some issues with it that I am trying to address.
- Head section parts are worn in some areas.
- Analogue XLR ins, left and right input levels stay matched when recording for 5-10 minutes then the left side would loose input level by 20-30% and stay there. Sometimes it might go back to normal. This also occurs with the RCA inputs but is more consistent and stable.

Head section
Some of the rollers (ie. tension, pinch) are worn on one side, but luckily I am able to reposition it as it is held into position with a screw. As for the lifters, they are worn and damaging the tape.


These lifters are different, and based on one post I read for a different reel to reel machine, lifters are hard pressed to the arm. Using a vice grip and rubber to prevent damaging, you manually rotate it. Does anyone know if it is the-same for the Tascam 52?

Here is the explosion drawings from the Service Manual - I think it is either 80, 81, 83?


Anyone know if getting at this lifter and removing it, is easy. From my understanding the head block is on top of this. So if I remove the headblock and adjust the lifter, do you think I would need to do any calibrations afterwards, or would this be simply re-assembling it and it will be as before?

I saw sleeves for lifters being sold for a different reel to reel machine and was wondering whether I could do it with the 52 and slide a sleeve on top of the lifter? Anyone tried this and would it work?

Input Issues
Not sure where to start here to try and fix it? I usually just do gain staging to try and get the unit recording and playing back with matched stereo using the input and output knobs.
I am thinking the levels mismatch might be cause by the damage the lifters are causing to the tape when fast forwarding and rewinding?

Any help appreciated!

Thank you.

 

[sweetbeats]

No time at the moment but I’ll respond with more detail later.

How long have you had this machine?

What kind of tape are you using?

If you’ve owned it for awhile did you switch tape type and if so what type of tape did you used to use?

Did it come with any tape when you bought it, and if so what type of tape?

Your pinch roller needs replaced. I highly recommend the Athan rollers.

 

[horeq]

Hi sweetbeats, are you talking about the roller next to the lifters (with the green arrows)? Those seems fine, theres no roughness, just discoloration. Its the lifters I am concerned about, their rough. Looks like they might have been rotated before.

I have only gotten it and I am using Basf 468 tapes.

 

[sweetbeats]

No. I’m talking about your pinch roller. The one that engages the tape to the capstan shaft.

The metal roller in between the sync and repro heads is the scrape flutter idler.

 

[rob aylestone]

It does look like it has put in the miles, and certainly the left guide has wear in the 'wrong' place so may have been spun - the other seems to have wear in the wrong place, but is that one actually spinnable? I suppose it must be with wear there.

 

[sweetbeats]

Again I’ll respond in more detail later. Honestly it doesn’t look like a high-mileage machine. I have a 58…my second one…long deep history with the 50 series.

I think your signal drop problem is edge shed on your tape. I’ll talk more about why and maybe what can be done later.

Terminology…so we use the same terms, the components in your tape path from supply side tension arm roller to takeup side tension arm roller are:

Tach roller
Incoming guide
Lifter
Erase head
Center guide
Record/sync head
Scrape flutter idler
Lifter
Reproduce head
Outgoing guide
Capstan shaft/pinch roller

 

[sweetbeats]

So here’s the thing…I think the tape path on your machine was establish by Quantegy/Ampex tape. Tape width has an international standard. There is generally a 0.001~0.003” error allowance. The tape slitting equipment used by Quantegy/Ampex was not this stable or accurate…I don’t recall for sure but I think I saw a spec once the best they could do was keep the variance error to 0.005” or 0.006”. So the risk was if they tried to slit to the specific width standard, because of the variance error or “slop” in their slitting equipment, it might be possible for tape to go out the door that was too wide. We’re talking only 0.002” or 0.003” too wide, but in this world too wide is too wide. SO…they chose to slit tape slightly more narrow than the standard to avoid tape being too wide. What this means is, in many cases, the wear path is 0.001”~0.003” more narrow than a wear path that might be established using tape which was slit more precisely to the standard…like the AGFA/BASF/EMTEC/RMG/RTM lineage…which includes your tape. It’s hitting the edge on one or more tape guides and on the lifters…You can see the fur on the center guide, And I think I see build-up on the record/sync head too.

The first thing to always do is get the transport functioning correctly before tackling electronics. Your level issue might just be related to a buildup of debris…it take a surprisingly little amount of debris to cause a problem. On a Tascam 388 a spec almost too small to see is enough. Ask me how I know this. Part of transport setup is making sure that the hardware is within spec. Like, your pinch roller, which looks glazed and hardened. At least from what I can see. And the manual has very specific instructions in it regarding the adjustment of the three tape guides. Do not…I repeat, do not just start adjusting one guide…the 50-series is a bit of a PITA to get the tape guides correct because they are all independent and adjustable, but all interdependent at the same time as far as their influence on the tape, and also because of where the tension arm rollers are located, which are essentially rolling guides as well. Follow the procedure in the manual…which may involve needing to tweak the tension arm roller heights. They all play on each other, those 5 height adjustable guides…like I said, PITA. But once it’s set right it runs nice. You may want to start by trying to put the once guide back to where it was, and see if you can wear your tape in or also dress the edges of the wear path with your BASF tape. Pick one reel to be your “shop tape.” What I mean by all this is sometimes in a situation like yours if you run your tape in fast wind with the lifters defeated through the tape path it will take care of the shedding problem with that reel of tape and also maybe dress the edge of the wear path enough to reduce the issue with new reels of tape. I know it sounds a little barbaric. But it’s a legitimate measure to try. And tape guide rotation: yea you can rotate the tape guides to a fresh surface, but be aware that changes the geometry of how the tape mates with the heads slightly and the wear path that’s already established…the flattened faces on the heads. If you talk to the experts, the people who professionally relap heads and optically align and setup tape paths, they will tell you to never do anything to impact that geometry unless the heads are being relapped and you’re starting fresh. If you do it now, rotate your guides, you’ll start a slightly new wear path on your heads and have two wear faces. It may impact performance until the new facing is completely established, which could take awhile. Or in some cases cause performance to be off-standard permanently, or at least until the heads are relapped. So in your case, if I’m correct you are dealing with a tape width/wear path issue, the only true way to fix it is to rotate the guides, and relap the heads. And ask the tech you laps the heads to cut edge slots in the heads so this never happens again with the heads. If you want to do something less it’s fast winding a reel of tape a couple times with the lifters defeated and cleaning things up thoroughly after each pass. If you want to roll the dice a little you can rotate the guides and at least take that variable out of the picture regarding the edge shed, but understand there is some impact to tape-to-head contact and the geometry there. And then always mind the setup procedure for the guides and go through it to get it right.

Lifters…IIRC the lifter posts are swedged into formed steel arms on a 50-series…I think I have a set for the 58 somewhere. Or actually one spare used and one NOS. I’ve rotated lifter posts before. You get a small set of vice grips and clamp them as close as you can to the base of the post, and carefully clamp the arm in a bench vice, and then gently rotate. The vice grips leave tooth marks. That’s how you have to do it, otherwise they just slip... But that’s one reason you clamp the jaws as close to the base as you can because then the marks are generally non-visible once mounted with the dress panel in place. You have to remove the pinch roller, dress panel and headblock assembly to get to the lifter assembly. You don’t remove the heads or guides or anything from the headblock. All that is mounted on a single block. You’ll see it when the dress panel is removed. There are three socket head cap screws that fasten the headblock assembly to the transport plate. On the 58 the heads plug in via connectors to a small PCB. If the 52 is the same then it’s just remove pinch roller, remove dress panel, remove headblock assembly screws and unplug the heads and the whole thing comes out. Then you can get to the lifter assembly. You can rotate the guides anytime…there will only be benefits there and no detriment to the rest of the tape path geometry and such.

Hope this is helpful.

Ask any additional questions if needed, like follow-up or if I missed something.

 

[jamesperrett]

While Agfa/BASF PEM468 usually plays with no shedding, occasionally you may get a bad one and I don't know of any way to stop it from shedding. Repeated plays will just mean more shedding and from personal experience I know that baking will make it worse. I would give the tape path a very thorough clean and then try a known good tape.

 

[horeq]

Thanks sweetbeats for that informative reply and also to everyone else for their input!

I did adjust the tension rollers and tape guides because on the feed tape side, the tape was rubbing on the body of the unit as it went from the tension rollers to the big rubber pinch roller. When I was comparing the tension rollers on both the feed tape side to the receiving tape side, that the tension rollers were higher(by less than 1mm) and cleared the body of the unit, so I matched it and gave enough tape clearance.

I also adjusted the tape guides as I noticed the tape would go outside the head pickup area by a fraction, but wanted the tape not to go outside that pickup area. I thought this could be the reason why the left input was lower, but it did not fix the issue.

Good points sweetbeats, I never thought of it that way, regarding adjusting one part can change the whole behaviour of the machine that it was originally set up for. The spooling on the receiving reel, seems off now and is not centered to the reel as before. I do notice some new angling happening with the tape when it travels.

The transport on this is very good. I am really impressed by this unit. Everythings all digital now adays, and its very hard to appreciate good electronics and mechanisms like this anymore.

I did some more tests with the level matching issue with the left and right inputs. I don't know whether this is something is about to break down in the unit, but the levels would be matched and be fine for a couple of minutes use, then one side would go lower by 30% and remain there till I turn it off and use it the next day. Could it be a bad cap or opamp about to go? I thought at first that it could be the tape not covering the head area properly or the tape being worn out on one side due to the heads and guides issue but now I do not think so. Also once the left input lowers, it remains at that level difference and does not change drastically. It does fluctuate though, like it moves between 0.1 db on each side. eg. Left side - 10, 10.1, 10, 9.9, 10.1, 10.

Thanks for the instructions on how to access the lifter, that will be useful if I decide to take that plunge!

 

[horeq]

Do you think the level drop could be an issue with requiring de-magnetizing?

 

[sweetbeats]

Do you think the level drop could be an issue with requiring de-magnetizing?

No I don’t think so. In my experience a machine needing degaussing will have some diminished HF response, and in extreme cases there will be small pops or crackles imparted to the signal printed to tape. I always degauss a machine that’s new to me just because I don’t know when it’s been done, and then every once in awhile for preventative maintenance or if I notice symptoms.

 

[sweetbeats]

Thanks sweetbeats for that informative reply and also to everyone else for their input!

I did adjust the tension rollers and tape guides because on the feed tape side, the tape was rubbing on the body of the unit as it went from the tension rollers to the big rubber pinch roller. When I was comparing the tension rollers on both the feed tape side to the receiving tape side, that the tension rollers were higher(by less than 1mm) and cleared the body of the unit, so I matched it and gave enough tape clearance.

I also adjusted the tape guides as I noticed the tape would go outside the head pickup area by a fraction, but wanted the tape not to go outside that pickup area. I thought this could be the reason why the left input was lower, but it did not fix the issue.

Good points sweetbeats, I never thought of it that way, regarding adjusting one part can change the whole behaviour of the machine that it was originally set up for. The spooling on the receiving reel, seems off now and is not centered to the reel as before. I do notice some new angling happening with the tape when it travels.

The transport on this is very good. I am really impressed by this unit. Everythings all digital now adays, and its very hard to appreciate good electronics and mechanisms like this anymore.

I did some more tests with the level matching issue with the left and right inputs. I don't know whether this is something is about to break down in the unit, but the levels would be matched and be fine for a couple of minutes use, then one side would go lower by 30% and remain there till I turn it off and use it the next day. Could it be a bad cap or opamp about to go? I thought at first that it could be the tape not covering the head area properly or the tape being worn out on one side due to the heads and guides issue but now I do not think so. Also once the left input lowers, it remains at that level difference and does not change drastically. It does fluctuate though, like it moves between 0.1 db on each side. eg. Left side - 10, 10.1, 10, 9.9, 10.1, 10.

Thanks for the instructions on how to access the lifter, that will be useful if I decide to take that plunge!

A fluctuation of +/-0.1dB on a tape track is not uncommon. Maybe others have a different opinion on that…but there can be a multitude of reasons for that. Generally the wider the tape track and format the more stable that is. But even +/-0.3 or more dB on an edge track of a multitrack machine I just leave alone. It’s really difficult to get rock-solid stability…there are so many factors at play. But generally on a 1/4” halftrack machine it’s easier to get that stability. I want to return to the points about the tape path setup. Do you have the service manual? Are you looking at the instructions for the adjustments of the tape path components? Do not use the tension roller height adjustment to try and get tape spooling in the middle of your tape reels. There is an independent adjustment for that for each reel table and it’s the last thing you adjust. You start with the three guides in the headblock assembly, adjusting those so the tape is traveling dead center across the heads, and then contacting the tape guides as indicated in the service manual. I assume it’s the same for the 52, but tape should be touching the bottom of the incoming guide, the top of the center guide, and the bottom of the outgoing guide. The tape should be traveling down the center of the tape path and touch the guides as indicated:



There should be no curling or lifting at the edges of the tape where they touch the guides. Again, they are inter-related as far as what how one adjustment effects another. The closer you get to things being “right” the easier it is to maybe make a tweak to one adjustment. And then the tension roller height adjustments play into it because if the my are too high the that makes it hard to get tape to travel in the center and touch the bottom of the incoming or outgoing guides in the headblock. If they are too low the tape lifts or curls in the guides at the bottom and you can’t get the tape to travel in the center of the path without this happening. And it can skew the tape so it wants to be too high at the center guide and it’s curling or lifting there as well. These are just some examples of how those five adjustments interact and you have to start with the center guide and work your way out, making tweaks different areas to get desired results with each, and check and re-checking each adjustment as you go since the interplay with each other. And then like I said you adjust the reel table heights last after the tension roller heights are set for wherever is demanded by the incoming and outgoing guides in the headblock. It can take a couple hours and some good lighting to get it all sorted out. And as I said earlier I try not to mess with it, and then only strategically after analysis of what is not right, to avoid causing more trouble, because in some cases just one little adjustment of one component is all that’s needed to make it right. And in other cases somebody has gone and messed it all up and you have to start at square one. But it’s important to study the manual and the process and try and get a grasp on what each adjustment does and how changes to that adjustment impact the behavior of the tape in the rest of the tape path. At the end of the day you want tape traveling down the tape path across the center of the heads, and just touching the bottom edge of the incoming and outgoing guides, and the top of the center guide.

If tape is curling or lifting slightly at one edge it can cause slight level variations, as can skewing. Tape tension can have an effect too…changes in the tape tension. A bad pinch roller can cause this. Look again at my list of tape path component labels above. I want to make sure we are using the same terms so we can know we are talking about the same things. For instance you referred to “pinch roller” but I think you were talking about the supply side. The big roller between the tension arm and the incoming guide in the headblock is not a pinch roller. It doesn’t pinch the tape. That’s the tach roller.

Can you post a pic of your pinch roller? The one between the outgoing guide of the headblock assembly and the takeup side tension roller? The one that engages the tape to the capstan shaft.

Regarding your diminished level issue, if it diminishes with time, and stays that way after you clean the tape path and try again, then it may be an issue with a bad solder joint or bad connection that becomes problematic as the unit warms up. Have you re-seated the amp cards? If not, try that and see if that helps. If it doesn’t, try swapping the amp cards to see if the problem swaps channels…follows the card.

 

[horeq]

Do you mean this pinch roller?


I will give reseating and swapping the amp cards a try. I think these are it, their called Record/Reproduce PCB Assembly.

Are these simply unscrewing the screws for the clamp on the right, unplug the grey cable and pull the card out? Not sure if I need to access it from the rear also and undo something?

 

[sweetbeats]

Yes on the pinch roller. That is the pinch roller. The only pinch roller. There is only one. And it looks shiny, hardened and glazed. The Athan replacement pinch rollers include new bearings, a mechanical noise damping core, long lasting and more stable/consistent material for the roller portion, and are precision manufactured. Plus the price is comparatively reasonable. I see people charging over $200 on eBay for replacement rollers of unknown quality without bearings…practically a scam.

And yes those are the amp cards. I do not own nor have ever seen or touched a 52. So consult your service manual to be sure, but from your pictures it appears you are correct…remove the bracket at the right, disconnect the cable from each card, grasp each corner of the card with each hand and sort of rock and pull, leverage your hands against the face of the machine if you need to do you have better control as you work the card off of its connector…if they’ve never been out or it’s been a long time they may be stubborn, but they are designed to come out, they plug in using card edge connectors at the backplane.

Start by reseating them…don’t swap…just unplug and plug them back in a couple-three times each, then test and see if the problem still persists. If it does then swap the cards and see if the problem moves to the other channel with the card swap.

 

[horeq]

I think I know why it dropped on one side drastically. If RCA is plugged in with XLR, due to the amp booster, it will cause a drop in the XLR. So I inserted some RCA's in and out and noticed an improvement. Must be a funny solder somewhere in that area. It still has about 8-9% difference, which isn't bad and it is better than before?

I did some gain matching using the input and output knobs and this is the best I could come up with. This is from white noise recorded to tape. I noticed that one side drops early at about 4K upwards.

Can this be fixed by adjusting the trimpots from the amp card, or is this something that the heads might be doing?

Is this an acceptable frequency response? I think that 5db drop at the high end is too much, how much of a difference would be thought of as acceptable?

Also did some temporary sleeves using straws for the lifters, and this is the kind of dirt and shred I am getting.


Does this look like the result of NOS tape deteriorating?

Thank you.

 

[jamesperrett]

That doesn't look good. Agfa PEM468 will either play completely cleanly or, just occasionally, it will shed fairly badly. I would expect the BASF version to be similar although it is newer. It may be coincidence, but the problem 468 tapes that I've encountered have mainly come from US studios.

What level were you using when you were measuring frequency response? I would expect the response to be pretty much flat to 15kHz at 0dB (assuming a reference level of 320nWb/m).

 

[sweetbeats]

So that looks like flaky shed. Step 1: get some new known good tape. Step 2: get a new pinch roller. Step 3: go through the transport setup and adjust procedures in the manual…tape path stuff, so it is pulling tape correctly. Step 4: go through the electronic calibration procedures…align the meters…set playback level…set record level and bias.

Your problem might simply be corrected with a rebias and HF record EQ adjust, but, and I can’t emphasize this enough, that is a waste of time unless you do Steps 1 through 3 first.

 

[horeq]

OK, we can remove the tape from the equation. I just remembered that I use the exact tapes on my Akai 4000XL with none of this tape gunk, just some light coloration if any. I need to refine my rotation of the tape guides, as I think due to my eyesight, I am not picking the smoothest surfaces. Also, I think the heads may be a little rough?

 

[sweetbeats]

If the heads are “rough” and you’re starting to mess with geometry (rotating guides) then you need to consider a relap.

 

[horeq]

I have done the tape guide adjustments and also the reel plate height.


Regarding head relap, I have a dremel, can I use one of those furry attachments and do it myself?

Does the tape stuck to the heads, a good indicator that it is rough in that area?


If I get it relapped, does that mean I need to have this unit calibrated - ie. adjust azmuth, use oscilloscope, and use other tools?

Trying to weigh out whether I should just leave it as it is, I do not have the budget to send it off to a professional, trying to do DIY.

I am considering just using an EQ in my DAW to match the left and right frequency response.

My priority is to stop the shedding/damaging of the tape when I use this unit.

Looking at the sync head, I think its worn out rough badly. Shouldn't it be curved, it looks flat and has some sharp edges to it? What do you think?


Also, looking at the heads, do you think these have been relapped before?

Thank you.