Well it was free (or) the Trio kw55 project

[tyeeslayer]

This was just given to me and it will be my first venture into the world of tubes. WOW what a mess!!!! Looks like it has been in a barn for many many years. Will this be a labor of love or aggravation. I think the missing knobs may be the hardest to replace. I guess it is time to build a dim bulb tester unless I can find a nearby variac. Other then a through cleaning and checking for broken wires and such is there anything I should do before testing? Should I recap, rewire or remove and have all tubes checked before testing?
I will keep this thread updated as I progress w/ pictures and wins and losses. I look forward to all the gurus advice as well.

Wish me luck.

 

[tyeeslayer]

A few more pictures

I hope the underside looks better.

 

[Diverted]

I've seen worse! Take it slow, check for continuity on all coils, IF, power and audio transformers, etc., first thing Make sure the parts that are there aren't broken and have to be replaced by things you might have a hard time finding, before you spend a ton of time cleaning, rewiring crumbling wire, etc. It'll save time in the long run in case there's something dead. That should be a fun project though! Just imagine how much it's going to kick ass when you get it playing

 

[gadget73]

oof, thats filthy. I'd be spending time with the vacuum cleaner, some paint brushes, and maybe some carefully applied compressed air to get the worst of the filth out of there.

second checking the output transformers. Japanese gear was not known for having high quality capacitors, and they would fail in a way that caused very high current draw. Its possible to cook a transformer from that.

 

[Dandy]

That (very nice) receiver is likely to have a lot of grey caps underneath and some can caps that will ALL need to be replaced.

But the place to start is to check that the power transformer is working.

I posted a link to the schematic in post #3 of this thread: http://www.audiokarma.org/forums/showthread.php?t=377432

 

[tyeeslayer]

A little update

Got a little cleaning done. I think even if I find major problems I will need to part it out anyway.
What will happen if I plug it in as it sits in these pictures, without any tubes in it so I can check the power supply? Should I still use a dim bulb tester for this step?
Thanks.
On the up side the underside looks clean.

 

[tyeeslayer]

That (very nice) receiver is likely to have a lot of grey caps underneath and some can caps that will ALL need to be replaced.

But the place to start is to check that the power transformer is working.

I posted a link to the schematic in post #3 of this thread: http://www.audiokarma.org/forums/showthread.php?t=377432

Thanks for the link I'm gonna need that for sure.

 

[Dandy]

Yes, do use a dim bulb tester for the first power on switch without tubes. There are some voltages on the schematic that indicate the zones you're looking for, though those figures are with tubes in.

Believe me (and others) and place an order for all those grey Elna caps. I also found that some of the slide switches needed to be replaced. With bad switches and caps all over the place, it is difficult to do other fault finding.

It also looks like there's been some work on caps in the top left of your second picture in post #6. Can you take a closer look and picture of that area?

 

[battradio]

Check the volume control , have seen more than one of these with a bad ones , they are very hard to find replacements for them , they open and are just not noisy .

 

[tyeeslayer]

Yes I was checking some of the caps and a lot of them were way off.
Where is the best place to get these?
I posted a pic of suspect replaced caps. I assume you were referring to the ones under the black tape.

 

[Pio1980]

All the e'lytic signal caps and all the under-chassis filter caps need replacing. Most likely so will the bigger ones in the power supply. Also the oily paper signal caps, all of them. These Big Kenny/Trio receivers were a whole lotta well built radio set and well-worth rescuing.

 

[tyeeslayer]

The bulb went dim, 1st good news. Next to do, check transformer voltages.

 

[sony6060]

If one likes the smell of hot dusty tubes, you hit the mother load.

 

[tyeeslayer]

What brand of caps and where to order? Not the most expensive, just good ones.
Any thoughts on cleaning up the rusted chassis? Clean, sand it and tremclad it? Or just clean and leave it as is?

 

[jwhvt]

I used JustRadios for my KW33. They have an easy to use order form. You'll get some great help here on this project if you decide to go through with it!

Before:

After:

 

[gadget73]

the yellows work well and they aren't expensive. Many will say they don't sound all that amazing, but they will make it electrically operational and reliable. Other reasonably inexpensive options include Sprague 716p orange drops or Soviet K40Y and K42Y caps.

 

[Jcricket]

I have serviced two of these trio's They are good amps. I recommend orange drops almost exclusively. I love them.

Battradio mentioned a bad volume pot. I have to hardily second his recommendation. I have seen several(maybe 5 or six of these old trio/kenwoods) that had bad, non repairable pots on the volume control. They are for all practical purposes unobtanium. Otherwise, you have a really goos unit there.

Good luck!
Mark

 

[Pio1980]

It may be possible to find a suitable replacement sans switch of somewhat different resistance that is still adaptable. I think my Kenwood has the same problem as does as an early version Sansui 1000, I just haven't gotten back around to them lately to try the pots.

 

[Jcricket]

The volume knob on these kenwoods had these parameters:
It was a dual gang, 1meg pot, dual control(a control for each pot as this was also the balance control), center taped for loudness. If you are able to find this, then you would still need to deal with shaft size so as to be able to install the original knobs.


I did find at one time, a lot of five of these dual pots. They worked functionaly, but the knobs never fit.

Hopefully it will be a non issue for this unit.

 

[Pio1980]

A 250k pot may be usable if some adaptations made to accommodate it.
I have a couple of these I think the knobs will fit from Rat Shak purchased 1980s. They may still be available from RS.

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