This is a very strange problem... I accidentally made mine in protection mode while I was doing connections on the phono.... The amp is OK.
Mine is more than 1 hour before the relays clicks. The delay cap I believed C403 is ok. I checked all the components on the protector but I didnt found faults. I also changed all the capacitors coz I suspect there might be leaking but still didnt clicked...
I removed the Li/Ri and even the BP caps C409-C412 to make sure no DC coming in but no luck. But If I disconnect R413 relay fires instantly. This very straged coz all those caps, diodes, TR407 and resistors on the DC sensore side are OK.
Without doing anything, it came to normal, about 4 seconds it fires. Im worried this problem might come again..
So, I studied the protection circuit , as per service manual im having over voltages. Its main power supply is 100VAC, Im supplying it 120AC.
It gets more than 50% increase on the protectors DC voltages.The main +B3 should be 8.9V but im reading 15.++ volts.. The C402 (rated 16volts) is getting 17.++volts, it should be 10volts only. This extra 7volts makes the TR402 to produces extra 6volts on the main +B3
To compensate this over voltages I increased the value of R402 from 2.7K to 8.5K. Now the voltages came so close as per service manual, a bit higher, Im not making it perfect coz If supply it with 100VAC under voltage will happen.
I ran it over night and it worked well, I returned all the original caps and ran it overnight again,no more problem. To test if the protector works I tapped 4.5volts on the Li/Ri the relay goes off, I touch the R413 the relay goes off, I touch the input (amp) at high volume to generate enough DC, the relay goes off. It's normal now.
This is a mistery to me.... It was working before at overvoltages.
Anyone there experienced the same problem. Is this overvoltage suddenly caused the problem?
Hi pradigmshift, whats your main AC power supply?