38 deck--intermittent playback

  • Thread starter Thread starter ithacadude
  • Start date Start date
more pics...

ok, I found a glut of more pictures I took in process that might be of use (sometimes easier to see it than talk about...)
you can see I had my unit on the side - i must have switched from side to side to get both the side's screws off (?) maybe you'll naturally hit upon a better position. for some reason I avoided having the thing upside down, though I don't see any real reason why that would be bad. It was nice to have on its side when all the screws were coming off because then it would not have anywhere to fall to...
Tascam 34 1.webp Channel boards out...

Tascam 34 2.webp Pre connection detach pic...

Tascam 34 5.webp Post connection detach pic...

Tascam 34 6.webp here's what you want to be working with - easy to clean with toothbrush and you can easily get to both sides for testing.:)
 
sweetbeats said:
Rectifying a cold solder joint or broken joint is generally just a matter of reheating the joint to melt the solder and its a good idea to add just a touch of new solder.

For working on these kinds of joints you want to have an iron with a fairly small tip and you need to keep it clean as you work. If it is dirty it will hamper the ability of the heat to transfer to the joint you are working on and you end up heating the whole area waiting for the joint to reach the melting point. You want to be able to work pretty quickly or you may damage other bits. I also suggest you leave the channel card plugged in as it will keep the pins lined up and help to disperse heat. Might be wrong on that idea see what others say. Anyway, I use a wet piece of t-shirt material to wipe the tip of the iron, and I keep a small utility knife handy to scrape any stubborn coke off that builds up on the tip and won't wipe off.
Click to expand...

Great advice here, much appreciated!
 
thanks for the pics
I'm having a similar problem on my 38 outputs, so i will try all of this stuff also. I've removed the 2 problem channel cards not playing back. It can record the track, and the meters will move according to what is playing but no output out of 1 and 2. Check the mixer, cables, dbx. Just got to buy some de oxit, for the pins from the motherboard, swap channel cards and try some of this stuff out.
 
gg38 said:
thanks for the pics
I'm having a similar problem on my 38 outputs, so i will try all of this stuff also. I've removed the 2 problem channel cards not playing back. It can record the track, and the meters will move according to what is playing but no output out of 1 and 2. Check the mixer, cables, dbx. Just got to buy some de oxit, for the pins from the motherboard, swap channel cards and try some of this stuff out.
Click to expand...

No output from 1 and 2 when in eithd "sync" or "repro" modes? After swapping channel cards are you still having the same issues?
 
I still haven't swapped them out yet. I want to get deoxit first and clean the contacts first, put them back in the same place, and then if it doesn't work swap. But, yes no output on 1 and 2 in either mode, sync or repro head.
 
Clean the rca jacks on the rear panel with de-oxit as well. I found some really nice little long and round brushes that are great to get down into the female portion of the rca's. Have you swapped output cables coming from the deck and made sure it just not a bad cable issue. You can record to 1 and 2, and get the VU meters to function on playback when in sync or repro mode right?
 
Are tracks 1&2 on the same card or is it like the 388 (and others) where 1&3 are on one card and 2&4 are on another?
 
rickb said:
Clean the rca jacks on the rear panel with de-oxit as well. I found some really nice little long and round brushes that are great to get down into the female portion of the rca's. Have you swapped output cables coming from the deck and made sure it just not a bad cable issue. You can record to 1 and 2, and get the VU meters to function on playback when in sync or repro mode right?
Click to expand...

I jumped the gun...you are getting the source signal on 1 and 2 to come through the deck? If you ever get a chance to get a Teac MB-20, they are pretty handy. Also consider getting a tone generator to send signal...I bought a Fostex TT-15 cheap, and Teac made a TO-122A.
 
well I've torn this thing down and cleaned all the motherboard connections really well and tested for continuity. sometimes there would not be continuity but then you check again, scratch the probes around and it appears. powered up and still issues with tracks 2 and 4, no meter on 2 but signal from both heads, no signal or meter from repro head on 4. cleaned, resoldered motherboard output connectors, tested several more times, cleaning again in between trials--random card swaps--no good. I think I may give up soon. can't seem to find the problem--all channels seem to have continuity in the same places. time to go for a walk and let this pile of junk rest.
 
ithacadude said:
well I've torn this thing down and cleaned all the motherboard connections really well and tested for continuity. sometimes there would not be continuity but then you check again, scratch the probes around and it appears. powered up and still issues with tracks 2 and 4, no meter on 2 but signal from both heads, no signal or meter from repro head on 4. cleaned, resoldered motherboard output connectors, tested several more times, cleaning again in between trials--random card swaps--no good. I think I may give up soon. can't seem to find the problem--all channels seem to have continuity in the same places. time to go for a walk and let this pile of junk rest.
Click to expand...

well, that's hard... I know I did end up dissembling and assembling at least twice before I got mine going. maybe you could test for continuity from the head to the lower side of the motherboard (while just the channel cards are out) if you get continuity at this point and card swapping doesn't change anything I couldn't imagine whats wrong.

I know my cheap multimeter was a bit erratic with testing (had to get the probes places JUST SO) - that could be part of getting erratic readings. if you take it apart again, be sure to test at every little connection between the top & bottom. be sure also that you've plugged everything back in when you test it ;) (it happened to me a couple times:o...)

also, I didn't notice if you specifically mentioned using DeOxit, but it purportedly has 'healing properties' (conductive residue) above and beyond isopropyl. if you havn't got some could be worth the purchase.

good luck
 
I've been using de-ox-id. different brand, I guess. hopefully just as good, anybody know? and I'm not going to give up! this machine is way too clean to not be back 100%. so I've got signal getting to all meters(motherboard-meter continuity), yet #2 meter is sometimes silent. can a meter be lazy/stuck even if it is getting signal?
 
ithacadude said:
I've been using de-ox-id. different brand, I guess. hopefully just as good, anybody know? and I'm not going to give up! this machine is way too clean to not be back 100%. so I've got signal getting to all meters(motherboard-meter continuity), yet #2 meter is sometimes silent. can a meter be lazy/stuck even if it is getting signal?
Click to expand...

It's highly unlikely for the meter itself to fail or be sticky. It's more likely that a connection to the meter is intermittent still.

Cheers! :)
 
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