Spec 1 protection mode

[xXColdShotXx]

My uncle has a Pioneer Spec 1 and 2. He says the Spec 1's protection light comes on without it being hooked into anything else. Has anyone ever had this happen to a Spec 1 Pre-Amp? Thanks.

 

[ZOOM]

It probably outputs a ton of DC offset. It's has many 2SA798 double transistors, and these drift with age.There are also way too many orange electrolytics in the signal path. These tend to go bad much more often than other types.

Not to mention the multitide of switches, all in the signal path. Look at the contact surfaces in these - they are totally black! Conduction is almost impossible. Needs full disassembly and aggressive cleaning.

This is a terrible pre-amp in original state. Absolutely chock-full of junky parts and a total killer of good sound.

 

[pustelniakr]

A Spec-1 does not have a protection light.

Rich P

 

[xXColdShotXx]

My bad, where would I start with testing on the spec 2 amp?

 

[mattsd]

A good place to start would be by checking the fuses on the power supply (the board in front of the filter caps), make sure they are all intact. If one of them is blown, stop, do not replace it and try to power it up again. We'll need to do some in depth troubleshooting. If they're okay however, then check the offset and bias, be sure to use clip leads for this or probes that have all but the tip insulated. Since the relay is not engaging you can check the offset at pin 15 on the meter amp board (the big board up front with the meters attached to it) for the left channel and pin 16 for the right channel. The bias is checked between pins 11 and 24 on the power amp boards, it should be near 30mV on both sides.