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Electronics => Repair => Topic started by: sean5302 on July 23, 2021, 08:27:58 pm

Title: Teac AG980 tuner amp won't switch on
Post by: sean5302 on July 23, 2021, 08:27:58 pm

Hi Guys.
I have a Teac tuner amp (receiver) that only goes into standby.
I checked the power rails and get AC voltages across the board.
I do have schematics which I got from here:
https://www.manualslib.com/manual/1741324/Teac-Ag-980.html#product-AG-980 (https://www.manualslib.com/manual/1741324/Teac-Ag-980.html#product-AG-980)

I see 240V AC on the main feed to the standby transformer and then 30V AC from that into the rest of the board.
I'm a Newbie to electronics and expected to see DC voltages across the caps and suchlike. There are a couple of diode bridge rectifiers but I'm only seeing 30V AC on the + and - outputs.
There is a large transformer that I haven't been able to test, other than that its resistance shows it be be OK.
The front display only lights the standby LED and one for each set of speakers, ie SPKR a/b and SPKR c/d LEDS are lit. Nothing on the main display.

I'm puzzled that all of the diodes I've checked show 30V AC on each side of them.
What am I missing, please?

Title: Re: Teac AG980 tuner amp won't switch on
Post by: bob91343 on July 23, 2021, 08:33:49 pm

What do you mean 'on each side of them'?  Where are your voltmeter leads connected?

Title: Re: Teac AG980 tuner amp won't switch on
Post by: m3vuv on July 23, 2021, 08:39:34 pm

i had the same issue on an old pioneer amp a while ago,it was the tactile on off/standby switch gone bad even tho it felt ok,maybe worth a look.