No input signal on my Teac 80

T

thereelman77

New member
I was in the middle of calibration and suddenly the inputs stopped working on my deck! A few minutes before, I had turned off the deck and removed a channel card to adjust a pot. And before the entire calibration I removed every card and cleaned the RCA jacks on them all. MRL calibration went well and when I started on erase calibration the signal faded slightly then just completely disappeared on all channels. no input signal on any of the channels. What could it be?

I was using my DVD players RCA outs with a tone cd I burned.
 
I really don't know what the fuse looks like on the cards. Are they the 2 large rectangular looking things that have OHM on them? Nothing looked or seemed wrong on the cards???? But I'm may not be looking at the right thing. Could they be possibly blown?
 
I'm not sure of the internal layout on the 80-8 but the fuse panel/circuit card would probably be somewhere near to the power supply at the top rear of the deck. They wouldn't be on the channel cards themselves.

Fuses look like a glass tube with a thin wire going through the tube, about the size of an inch worth of pencil with metal contacts at each end of the tube. If you can see that the wire inside the tube is broken, its blown and you need to replace it with the exact same type and rating. If you have a multi-meter meter, you can also test it for continuity by measuring the resistance of it. 0 ohms means its good. Infinity readings means its blown.

Cheers! :)
 
Well I found the fuses and none of them seem to be blown. They all have 2 thin wires coming down from the top onto a spring coil looking thing. None of them are disconnected from the spring I mean. I should have also noted before that the vu meters all still "jump" when I turn them on and off, as they did before. also I accidentally ran the output cabling into my mixer output,mplaying a tone, and it showed a signal on the meters......? All channels do that.
 
OK, so you visually inspected the fuses but didn't mention testing them with a meter. I should have stated previously that a meter test is really the only definitive test and to do that, you have to pull the fuse from the holder so that you don't inadvertently end up measuring the circuitry around the fuse instead of the fuse itself.

All that said, the meters moving and showing signal means there is power going to those circuits and you'll have to look elsewhere for the problem. Or is the problem now resolved? I couldn't quite tell from what you just wrote.

Cheers! :)
 
Yes, we checked it with the meter and we got a showing of 0. So it must be somewhere else? What else could it be, possibly the wiring on the inputs themselves?
 
thereelman77 said:
Yes, we checked it with the meter and we got a showing of 0. So it must be somewhere else? What else could it be, possibly the wiring on the inputs themselves?
Click to expand...

It's hard to say. You'd need to look at the schematics for all the circuitry that is common to all 8 channels and test those components and bear in mind that whatever you were doing during the calibration process may have triggered it. Might be something like a card not being properly re-seated or a short which may have occurred during the removal and re-installation of one of the cards. So a part like a diode or transistor might have failed. Or maybe a bad relay?

Cheers! :)
 
Start with the power supplies. If I could impart anything to those who want to learn how to fix these things. Check the voltages are what the schematic says they should be.
 
Thank you all for your help! I am glad to say that after a few weeks time (due to me being on vacation mainly) I fixed the deck.....Using the schematics above, I tested everything with my meter and got no signal flow. After some tinkering and sitting, I found out that the adapter from the channel card box to the main section of the 80-8 had gotten disconnected. I believe it is due to the fact that, up until the calibration, I had taken the RCA jack apart to fix some broken plastic and somehow loosened it up. My deck sits near-flat on about an 85 degree angle and gravity must have just unplugged it....Thank you and I will definitely be adding the schematics to my manual.
 
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