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From the bottom side unplug both white connector plugs to the amp board. Power it up and see if the relay clicks. If it does click, power down and plug the connectors back in one at a time to find out which amp channel is bad. if the relay wont close with both channels unplugged, check power...

The pilot LED on these frequently fail due to Rk6 (1.8K 1/2W) on the power supply either cooking or desoldering itself and usually destroying the solder pads in the process. Good chance the LED itself is OK.

Check the lamp fuse. It's on the rectifier board above the relay.

You don't need to do all of that to get at the relay.

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I'm not sure what a "true stepped attenuator" is. The 8100 (and 9100) vol section has a wiper that moves across a wafer with printed resistors vs a standard carbon resistive element. If it gets dirty it will be noisy. If you're asking if the vol section has detents (click click click), the...

If the big caps are leaking replace them, but I doubt they are. It doesn't sound like you are doing a restoration, just a repair. Definitely recap the 1710 board for the sake of reliability - there are only 5 caps. I used a film cap for Ck7 only because I had it on hand, an electrolytic...

w/o knowing your skill level I'll say it's a fairly difficult board to work on due to the tight space between the solder side and the filter caps. Remove all sheetmetal cover and the support pieces. Hang the back of the unit a few inches over the edge of your bench. Remove the white coupler...

https://www.audioservicemanuals.com/k/kenwood/ Some are better than HFE, many are the same thing. Edit - I forgot to mention - the power supply on these scream for an electrolytic recap. The zener diodes DZk1 and DZk2 run stupid hot and frequently cook Ck7 and possibly others. Note that Ck8...

Check your unregulated voltages +/-50VDC at pins 2,4,7 & 9 and your regulated voltages +/- 24VDC at pin 15 &12. Check DC offset on both amp boards at wire wrap pin #6. If they show just millivolts the amps are likely fine. If all of this looks reasonable, the likely culprit is the relay...

I took the pot to hardware store and picked one that fit. I lightly tapped the fingers down with a small hammer for a tighter fit, then pushed it in place.

I suppose it could be removed w/o destroying it, but I had no such luck. I ended up cutting it with a dremel cutoff wheel. A well stocked hardware store will have a replacement. it's called a push nut. The problem is almost certainly in the volume detent section. The spring breaks or...

Qk1(2sc1419) is heatsinked. It jut fails often. The other regulator (Qk5 I think) is a T0-126, which is odd. The board runs hot, it should be recapped.

The regulator transistors on power supply A are failure prone, esp Qk1. The bridge rectifier is wimpy, an upgrade is a good idea

Hopefully it's just a blown fuse. The fuse board is accessible by removing the top cover. Another fuse under the bottom cover. 4 or 5 fuses on the board. Remove each and test for continuity.

A 1/4" ratcheting box end wrench and a driver bit works well on those.

The rear bulkhead you're struggling with is held by 11 screws - 4 in each heatsink and 3 to the chassis. Once all 11 are removed it comes right off. Put about 3" of wood blocks or thick books under the amp to get it up off the bench prior to removing the bulkhead..

Read this thread

Check your regulated voltages on the power supply 1720-10 board. +/- 28vdc - 2 of each and a couple of 40vdc. Check your unregulated voltages +/-65vdc at the metal cases of the outputs or at the filter caps. Check continuity to ground wires on this board also. A missing ground causes all...

Move the switch on the rear panel to SEPARATE and feed a volume controlled source to the POWER IN jacks. If the distortion remains look at the amp section.

They are just wrapped, not soldered. There is usually a way to manipulate the board to work on it without disturbing the wire wraps. If you absolutely must remove one or a few, unsolder the pin from the board leaving the wire wraps intact then solder the pin back in when finished. Cutting the...

8v 250ma wedge from wjoe radio

Almost certainly.

Just that getting the coarse trimmer as close to zero a possible is super touchy, but if you can get it to about 10mv or so, either pos or neg, the fine trimmer then adjusts pretty easily

I'll just caution you about transistor subs on this amp - they are finnicky as hell. I doubt that it's either the 2sk58 or the 1400s. If you want to replace the 2sk58, get it from bdent.com