Teac 80 8 Channel Card Recording Issue

T

thereelman77

New member
Hi there!

So after my very odd problem with the pinch roller not touching and then touching the tape, I have only one other problem now with my sweet baby tape machine: Channel 3 will not record.
Now, I have been researching online and from what I have been able to determine by myself, it has to be something on the channel card....Problem is I don't know what. I have pulled out the channel card and compared it with another one that is working and they both look fine. My guess is that something may need to be re-soldered or a bad relay or something of that sort. The channel will receive an input signal from my mixer, in INPUT and NORM mode, but will not playback anything.
At first I thought it was a play back issue, but after flipping the tape over and playing in reverse (I had recorded on every channel but 3), I got playback thru that channel. So now I know it is just not recording at all. This seems like (I hope) a simple fix, but then again you never know.
My question is, does anyone have any input they could share or have had this sort of problem before and would perhaps know a fix?

I have most of the tools for taking care of the machine, everything except calibration tape, which I'm getting soon. I also have the manual but don't know where to start as far as checking the channel card, if that is the issue?
I'm going to demag. the heads in a few days when I actually have some free time, but I doubt that will do much for this issue.

Any thoughts, links, or help would be greatly appreciated!!!

Thanks!
 
Beyond visually comparing the channel 3 card to a known working channel card, you should also swap the cards to see if the problem clears up on 3 and moves to which ever channel you swapped it to.

If that happens, then you'll know for sure the issue is on the card itself and not somewhere else. Keep in mind that the signal from the input jacks go though other parts of the machine first before getting to the card and there is also the pathway to the record head itself which also a possible source of an issue.

You need to sit down with the service manual and have a good look at the signal path diagrams which will document all the points the signals travel through to know what you're looking for.

If the problem is on the card itself, then you have to look at calibration settings on it as well as looking for burned out parts or bad solder connections. A trim pot on the card might just be turned down.

Cheers! :)
 
The Ghost of FM....BRILLIANT IDEA MATE!

I switched the channel 8 card with the channel 3 card and it recorded onto the track. I then switched back the cards and I was still able to playback what I had recorded. So this verifies that it is the channel card?... Now I had my father, who is knowledgeable in the field of electronics, look at the channel 3 card while it was unplugged, it appears that the previous owner or someone else before, had re-soldered parts of the card that are on the: REC EQ, INPUT MON. LEVEL, MONT. EQ, REC. LEVEL sections... Ha ha, couldn't be anymore broad. I'm guessing that it would be something along the REC. LEVEL section, then again I do not know.
If I do not respond to this post in the next 18 hrs. do not worry, I will have 2 jobs I'm working tomorrow (actual job and gig) so I will get back ASAP once I get home.
It does not appear that anything is burnt out (nothing looks burnt at all, just slightly grimy).

However, I may just be ordering a new channel card from ebay and keeping the one that has the problem for spare parts.....I'd rather just keep the channel card I have, but I kinda need a fix now, so I will get back to you....

Thanks!
 
Good stuff!

Now you know that the problem is in that card and can either get it repaired and calibrated or find a spare on ebay...which hopefully works! ...With ebay, you never know for sure.

Cheers! :)
 
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