Technics SU 8080 relay

[chazix]

where location 119 and 120 in service manual ?

You'll those points on the tone amp circuit board, roughly in the middle. The diagram is page 5 in my copy of the manual.

 

[momolou]

where location 119 and 120 in service manual ? can not find it

View attachment 2696744

so my Negative probe in 119 and my Positive probe in 120 ? not Negative Probe on chassis ground and Positive Probe 119 or 120 ?

 

[momolou]

Can you read schematics?

If so, I would look for the voltage across the two coil terminals of the relay, to see if voltage is always present from when the amplifier is turned on.

If it is - it could be that the protect circuit is doing its job. Is there a "protect" indicator on the front of this amplifier?

I would then measure DC offset levels at the amplifier output terminals of the relay.

If your DC offset is OK, then I would look next at a fault with the protect circuit itself. This is usually pretty easy to diagnose - it could just be a capacitor or the relay transisitor

i have these Technics su 8080, with exactly symptoms, relay not working ( not hear any click), measure one coil to ground chassis = 50 volt, but when measure two coil terminal directly ( put lead postivie on one coil and negative lead on another coil terminal ) not show any reading

 

[momolou]

Can you read schematics?

If so, I would look for the voltage across the two coil terminals of the relay, to see if voltage is always present from when the amplifier is turned on.

If it is - it could be that the protect circuit is doing its job. Is there a "protect" indicator on the front of this amplifier?

I would then measure DC offset levels at the amplifier output terminals of the relay.

If your DC offset is OK, then I would look next at a fault with the protect circuit itself. This is usually pretty easy to diagnose - it could just be a capacitor or the relay transisitor

sorry to up these

if this voltage not present ?