tascam 388 rec/play issue and general pinch roller question

[moogmymellotron]

hi i just purchase a tascam 388 in really really nice condition. the only known issue w the machine was that it was not recording any audio. Though it would play back pre recording tapes very very muffled. the heads were reallly gunked up. i had to scratch gunk off the guides...

however after doing so, it was playing back a bit better and actually recorded some signal! my question is...could the entire issue be due to the heads being really dirty? they look okay underneath all the garbage. ive heard several people mention the recording bias?

also, just a general pinch roller question. I just put a brand new roller on my tsr8 and was just wondering how often do you guys clean the rollers and w what? thank you

 

[sweetbeats]

I generally clean the pinch roller when I clean the heads and I use a rag with plain water, or diluted window cleaner if it is stubbornly soiled.

What kind of tape are you running?

That may nullify the bias question, but the whole bias thing was started by me. Tascam's instructions for setting bias involve adjusting the output of the bias amps to a given level (150mV) rather than seeing how the level effects the tape. This is *okay* assuming you are using the very same tape spec'ed by Tascam which was 457. Many of us are using LPR35. I was not getting the right response on the tape when setting the bias amps at 150mV. I had to set them at around 300mV to start getting the right overbias. I called Tascam and they told me LPR35 has a significantly different bias requirement than 457 and to bias LPR35 using an oscilloscope (adjust bias for minimum distortion using the scope to monitor the distortion level). So I was going to do that and then report what level that set the outputs of the bias amps so all you 388 folks using LPR35 that don't have a scope could set your bias at a better level for that tape...haven't done it yet, but its my fault for getting the concern started in the first place.

Lastly, you BET a dirty head could prevent input and output from tape. You'd be surprised how little a piece of foreign matter Is needed to take it to zilch. Clean-clean-clean that tape path.

BTW, welcome to club 388!

 

[DuddyGuy]

You get that from that flake? I saw he posted up again and had figured out how to turn on, the on switch.... subsequently adding 120 to his asking price.

 

[moogmymellotron]

I generally clean the pinch roller when I clean the heads and I use a rag with plain water, or diluted window cleaner if it is stubbornly soiled.

What kind of tape are you running?

hey sweetbeats. ive only tested it w 457 so far. i felt perhaps the unit mightve been biased for other tapes since there was absolutely no output. i made an insanely noob mistake when i was picking up the unit, i was really excited being around the thing, so when i started to examine the heads i saw the horrendous, HORRENDOUS amount of crud all over the tape path, i just shrugged it off and assumed id be able to clean it up (ive repaired mellotrons in worse conditions)....well, after literally 9 or so hours or scrubbing, the heads are spotless, entire tape path is smooth as eggs. the heads seem to have some life left in them. though i will be replacing these guys soon.

AND to top it all off. IT WORKS NOW!! im pretty excited. im really keen w the 688 and the sound difference between the two tascam units is awesome.

 

[moogmymellotron]

You get that from that flake? I saw he posted up again and had figured out how to turn on, the on switch.... subsequently adding 120 to his asking price.

hey duddy.

no i havent followed up on this seller. so he relisted it and its "working" now? interesting.

 

[cjacek]

when i started to examine the heads i saw the horrendous, HORRENDOUS amount of crud all over the tape path, i just shrugged it off and assumed id be able to clean it up (ive repaired mellotrons in worse conditions)....well, after literally 9 or so hours or scrubbing, the heads are spotless, entire tape path is smooth as eggs.

This reminds me of a TEAC A-3440 that I picked up years ago. The owner barely used it, a low use machine but he never, ever cleaned the heads and probably used tape which once left a gooey, sticky mess and that dried up, leaving a hardened layer of stuff all over it. It wouldn't pass any signal and wonder why when you couldn't even see the tracks! I used a whole bag of those cotton make up remover pads (the best method) and 99% alcohol but I had to regrettably scrub pretty hard (in the direction of the tracks). Lesson here is that tape machines are not for everyone.

 

[sweetbeats]

Good job Moogy!

I'm using LPR35 just because I got a steal on 5 reels of it awhile ago...BASF branded.

You're using 457. Just set the bias amp output to 150mV as directed in the service manual.