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Help with Kenwood Receivers (KR-4070 & KR-5030)

NO!! Ultralinear speakers are no better than White Van

Not having heard White Van speaker systems, Ultralinear are the worst I remember hearing way back when.
 
Kenwood KR-4070

After listening several years to a KR-4040 I bought a KR-4070 for my father at a rediculous low On Sale price of CH Fr 175,-
This was in Zurich, 1980. Today, after more then 30 years it still functions well albeit the tuner section has lost some of its tuning capabilities. A good antenna signal helps. The display lamps have lost their life but it still sings through my sons Linaeum LS1 speakers.
A circuit diagram might come handy here. Anyone ?
 
bougan said:
Thank you for the information. It is indeed the power switch as the problem goes away when I hard jumper across the contacts.

I have been able to locate three switches NOS ("new old stock") and have ordered all three. These are Kenwood original parts and should correct the problem (at least for a few years). Because I have three switches I should be able to keep the unit operating indefinitly. These were not easy to find and I doubt if any more are available anywhere.

However, I found this interesting link for others with the same problem:

http://www.number63.ca/kenwood/kenwood.htm

Thanks for all your help!
Click to expand...

Where did you find the switches? Not that it matters if you cleaned them out... I have a 4010 that needs the switch... if you could be persuaded to part with one of them:) :deal:

edit - just realized how old the original post is. probably not going to get one of those switches... :(
 
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power strips

when y'all talk about power strips y'all are talking about like surge protectors right? there isn't something i'm missing?
thanks for your time, Brian
 
EchoWars said:
Nice find. I made a pfd of that whole thing.

The only thing he forgot is a safety cap. As the contacts close and open, there is a time when they are close enough to arc. This will eventually destroy the contacts unless a safety cap is connected across the contacts to eliminate the arcing.

A safety cap is a specially designed cap, and specifically rated to be placed directly on the AC line. It's design is such that it will fail open, not shorted. Digikey sells 'em, Panasonic Type VS, 10,000pf (.01µf), PN. P11423CT-ND.
Click to expand...

Echowars, does the safety cap go between the red and white wires on the outside of the grey power switch? So when the switch is open, the two lines are connected via the safety cap, and when switch is closed, you're bypassing the cap?

I just cleaned my contacts and am looking for the best way to extend the life of the switch as I suspect it will get pitted and the original problem will reoccur - just a matter of time. Also considered installing a AC relay
 
kr 5010

Where can I order the switch that is used in the retro fit? Great design, also where is the collar found ? thanks for the thread. Thanks
 
bougan said:
I recently purchased a Kenwood KR-4070. It works great except when first turned on... it initially flickers (the lights go dim and bright repeatedly and intermittently) and the sound is garbled for several seconds to several minutes before stabilizing. The problem appears to get worse as the unit warms up and is power cycled.

I previously owned a KR-5030 that did exactly the same thing (never resolved). I see from several other posts that other owners of the KR-4070 have experienced a similar problem.

Does anyone know what is causing it and how it can be resolved?

Thanks --

Tim
Click to expand...
hi Tim, 5/2/2026
Were you able to repair your KR-4070? Pwr SW/speaker selector is bad, you need to remove and open it to refinish contact surface.
I hope all is well
Rick
 
@2ricktis49

So that you're not awaiting a reply, the member you asked the question to posted that 20yr's ago, posted a total of 6 times, all in this thread and hasn't been seen or posted since then.
 
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