KLH Model 21 found at Goodwill today!

[Captainclock]

Originally Posted by zeno

On IC's it may not have used them. They went disco in the
80's IIRC. The way the IF is built I would NOT go
there unless needed.

If the main filter is not the hum check the outputs next
& any transistors direct coupled to them. They will probably get HOT fast.
Its probably the transistors mounted on the chassis in round
holders.

73 Zeno

According to a thread on AudioKarma where a guy had a unit that had the same exact issue as mine (where it hummed and no audio minus the blown fuse issue because mine hasn't blown its fuse yet surprisingly enough) they said something about the amplifier's coupling caps being bad which then in turn caused the output transistors to become fried like bacon, and once he replaced the coupling caps on the amplifier board and replaced the output transistors it worked fine for him. I'm hoping that's not what happened with mine because the amplifier board is going to be darn near impossible to remove because for some reason or another the amplifier board's mounting screws are covered in solder so there's no way to unscrew them...

Well I guess I can forget about working on the tuner board specifically on the vernier tuner mechanism because the screws wont budge and the heads keep wanting to strip out on me whenever I try to remove them, which tells me they used poor quality aluminum screws for that part for some reason, which is odd because the rest of the screws they used were stainless steel screws...

[jr_tech]

Originally Posted by Captainclock

According to a thread on AudioKarma where a guy had a unit that had the same exact issue as mine (where it hummed and no audio minus the blown fuse issue because mine hasn't blown its fuse yet surprisingly enough) they said something about the amplifier's coupling caps being bad which then in turn caused the output transistors to become fried like bacon, and once he replaced the coupling caps on the amplifier board and replaced the output transistors it worked fine for him. I'm hoping that's not what happened with mine because the amplifier board is going to be darn near impossible to remove because for some reason or another the amplifier board's mounting screws are covered in solder so there's no way to unscrew them...

Well I guess I can forget about working on the tuner board specifically on the vernier tuner mechanism because the screws wont budge and the heads keep wanting to strip out on me whenever I try to remove them, which tells me they used poor quality aluminum screws for that part for some reason, which is odd because the rest of the screws they used were stainless steel screws...

I'm guessing that the screws that attach the amp board to the heat sink might be filled in with solder to prevent removal... these *should* be left intact. the screws that hold the board/heatsink assembly to the chassis are the ones that need to be removed to remove the amplifier.
Try a better screwdriver on the tuner screws. Do you have any "Liquid Wrench" ?

jr

[Captainclock]

Originally Posted by jr_tech

I'm guessing that the screws that attach the amp board to the heat sink might be filled in with solder to prevent removal... these *should* be left intact. the screws that hold the board/heatsink assembly to the chassis are the ones that need to be removed to remove the amplifier.
Try a better screwdriver on the tuner screws. Do you have any "Liquid Wrench" ?

jr

No I don't have any liquid wrench, and I tried all the screwdrivers I have on the screws and they won't budge without just about stripping out the heads. So I don't know what to say about those screws. although those screws do have a very bad case of cadmium disease as well as a lot of other parts in this unit.

[zeno]

Try a drop of WD40 & let it sit a few days. Also heating them
may work. If the heads are stripped you can grab them with
a pair of dikes. Once started they come right out.

For small stuff get a set of ISO phillips heads. The jap stuff
needs a perfect fit or you cant get them out. They let out
a snap then turn OK.

KLH will use the US standard like a #2 phillips.
Buy highest quality so they fit perfect & dont strip like the screws.

73 Zeno

[Electronic M]

Originally Posted by zeno

Try a drop of WD40 & let it sit a few days. Also heating them
may work. If the heads are stripped you can grab them with
a pair of dikes.

PB Blaster penetrating oil is better than WD-40 at loosening fasteners. If you can grab the head with a vice-grip wrench those are often a bit better at gripping than dikes.