And then KA9100

SicMan

Fire up those speakers
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I have worked on over 60 of these in the past 20 yrs and I finally got one with a bad transformer. Damn.
Bought it and the description was doesn't power up. Oh ok no problem. Fuses were good too.
Long story short, no 43VAC both orange wires, no 30VAC either.
finally had to disconnect and try measurements. Nope. But the windings were in tack too.
Input was fine. AND it looks like it was not touched, all wirewraps looked original etc. Solder too.
I have spares. Strange.

0-transformer-9100.JPG
 
Have you tried harsh language? ;)

OH YEAH ! The wife heard me upstairs. Transformer is easy but what else is bad? (7 wires and 4 nuts and it drops out.)

Lately it seems that the "broken" stuff coming off the auction site has been messed with by several people
or has very serious problems. So they just dump it. :thumbsdown: Nothing really surprises me anymore.

Cheers peeps
:beerchug:

John
 
This is the right channel by the way if anybody cares.
After spending most of the afternoon and evening testing components yesterday, I changed the transformer
this morning (after testing it). Put it on a DBT and brought it up.
To be continued.
 
OK --- sorry about that. (Really I did that on purpose)
dogs-laughing.jpg
Well it came up ok, voltages ok, no problems. Took out DBT and fired it up and "we have relay click"
Only thing not on so far are the FP lamps. Now for some cleaning and testing before I decide what to do with this.
More hours? I have too many of these as it is.
Be back.
 
Well, refusing to accept the fact that only the transformer was bad I dropped the back panel
and yes, work was done. The large regulator xistors were replaced and the relay and diode
is about all that I can tell.
Morale to the story, "Can't fix it - put it on the auction site" somebody will buy it" All they had to do was go 1 more step
and they would have found the problem. OR, they knew the tranny was bad and didn't want to bother.
I think I paid a little too much for this but hey it's going to put another one in circulation.
Still puzzled why the transformer was totally bad. :dunno: I'm not going to lose any sleep over it that's for sure.
:boring::boring::boring::boring::boring:

Later peeps (Sorry, I don't put alot of details in my posts)
John
Just remember the aliens landed in the pyramids.

pyramid-blastoff.jpg
 
Last edited:
John, don't you know when you share Illuminati secrets they secretly trash your transformers. It all makes sense now.
 
I have worked on over 60 of these in the past 20 yrs and I finally got one with a bad transformer. Damn.
Bought it and the description was doesn't power up. Oh ok no problem. Fuses were good too.
Long story short, no 43VAC both orange wires, no 30VAC either.
finally had to disconnect and try measurements. Nope. But the windings were in tack too.
Input was fine. AND it looks like it was not touched, all wirewraps looked original etc. Solder too.
I have spares. Strange.
Any chance it had a thermal fuse buried a couple of windings deep in the primary side windings. Its a PITA but it is doable.
View attachment 929508
 
jimbo the primary windings measured ok, which was strange.

I found the last bug too

bug-kid-with-huge-bug.jpg
 
Hey SicMan, how did this Kenwood end up going? Amazing to think that someone could blow the power transformer! I thought they were indestructible. Shame on who ever gave up as well. When it comes to old gear like this, never give up! It's the only way to learn.

Cheers,

Andrew
 
Well I replaced the xformer, rebuilt the power supply section. (They used weird Asian transistors) brought it up and it worked fine.
I need to clean and lube pots etc and I'll probably rebuild the amp boards (offset pots are shot) and (shutter) remove the protection circuit board to really see
what they did. Then test and test some more. After that I'm not even thinking about it yet.
cheers peeps

Meanwhile in the other room.
burning_amp.jpg
 
I have worked on over 60 of these in the past 20 yrs and I finally got one with a bad transformer. . . . I have spares. . . .

You have spare KA-9100 transformers just lying around? That's impressive!
 
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