Kenwood 'control amplifier' troubles

[mhardy6647]

OK, here's a problem.

Our town Teen Center received the donation of a more or less complete 1980's vintage Kenwood stereo component/rack (NOT all in one) system. This is comprised of a power amp (billed as 125 wpc and pretty respectably hefty), a 'control amp', a dual cassette deck and CDP. The power amp works fine. The CDP has issues and isn't needed by them anyway, nor is the cassette (which we didn't check out). The problem is with the preamp.

The preamp is model KC-206. It's an odd hybrid of old-school manual controls (ALPS volume pot and graphic EQ sliders) and more modern controls (electronic balance L/R pushbuttons, on/standby power switch) and it is remote controllable. Needless to say, there is no remote with it. The preamp turns on and generally goes through the motions of working, but there is no output from the main outputs, regardless of source selected. Signal DOES pass through the tape monitor loops, though.

I am thinking it's in some way related to the LACK of the remote control, or some sort of odd mode that the preamp wakes up in (see also below). I tried some of our universal remotes with Kenwood device codes to see if I could get it to do anything, but no dice.

Any insight is greatly appreciated.

I'll describe the graphic volume display below.

Thanks for your attention!

 

[mhardy6647]

KC-206: more specific symptoms

When the on/standby switch is pushed, there's an internal relay click, a 'remote' indicator on the fluorescent display lights, and then the rest of the display lights. There's a graphic level indicator on the display that flashes thrice -- "and the number of the counting shall be three", as it says in the Book of Armaments -- and then lights at about the 40% level indicated... regardless of the volume control setting. The volume control is a pedestrian looking PC mount ALPS stereo pot... no sign of a motor drive for it, so I don't even know if the volume would be remote controllable. The graphic 'Balance' thingy does work, and is controllable by two little pushbuttons on the front panel.

No sign of a MUTE function on the front panel nor the display... there IS a section on the (well documented) main PCB inside labeled "muting" with about 6 epoxy transistors and a few passive components, but I don't know if it's audio muting per se or something to quell switching transients.

Again, if anyone knows anything about this model, or has a general insight that may be applicable, I appreciate the info. It'd be nice to rescue this preamp if possible.

Thanks!

 

[ModernClassic]

Hi,
I saw that the tape monitor 2 light is on, so it may well be it in tape mon. mode. Try to cancel it, if this failed then connect up monitor and record inputs of monitor 2 back to back and see if it got sound. Or simply connect up a CD player ( or any source ) to the tape monitor 2 input to see if it give you sound. I suggest to use a pair of head phones because the " remote " indicator worries me a bit - remote control or remote speakers?????
Hope this help.
Mc

 

[mhardy6647]

Tape mon 2 is just on 'cause I happened to have pushed it before taking the picture. All of the function selectors work (at least, the display changes when different ones are selected).

Remote cannot refer to speakers. It is a preamp, and does not have speaker selection built into it (though, as a MAC C-28 user, I do realize that some preamps do).

EDIT: my original comments sounded snide, which was not my intent. :-(
Thanks for the suggestions!

 

[glen65]

It might be worth looking into this....
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=14980&item=5728136838&rd=1&ssPageName=WD1V

 

[mhardy6647]

Heh, imagine that!?!

Ironically, All of the operating manuals were included with the donation... no clues in there, though.

Thanks for the suggestion and the link!

 

[glen65]

A unit like this dosnt normally go into mute
without some sort of indication on the display.
It will either display the word "mute" or show
some other type of symbol.

 

[EchoWars]

Well...now you know why it was donated. :yes:

 

[Stormseer]

I know this is an old thread, but found it on Google.
I have the same problem that you have with very little sound from the same system. Came across this Kenwood system while getting my oil changed (went to the local pawn shop to find junk components there). Told the guy what I was looking for there and he said he had a stereo at his mom's house in the garage. Kenwood amp, control pre-amp, tuner, double casette, cd player, surround processor all for $60.00. On the control amp the - remote - light is lit, and the volume level there is very low. I too don't have a Kenwood remote for it.
That's the problem, my best guess for very low to hardly and sound for an amp that's 125 watts per channel. If I could just find a remote to turn that function off I think I'd have sound! The system is strange since it's an early mix if digital & control knobs and buttons. Anyone know where to possibly find a remote?
Here's a link to what the system looks like, and some of the same components. I'd appreciate any help, or input my 1st post to this forum.

http://cgi.ebay.com/KENWOOD-KM-106-...6445861QQihZ002QQcategoryZ39783QQcmdZViewItem

 

[mhardy6647]

Sorry to hear of your problem; welcome to AK!
I tried various Kenwood codes on various universal remotes I had at hand. The preamp didn't seem to respond to any of them.

 

[EchoWars]

If you can find the PN for the remote, many are still available. Not cheap though...

 

[Stormseer]

Thanks for the welcome mrh, and your input EchoWars.
I know for sure the problem relates to NOT having a remote, but I think this is the PN.
KENWOOD A70-0260-05 *Nla* Remote Control Kc208 - I get that info from this page http://www.vancebaldwin.com/ I really would like to make this system work, and the guy I bought it from (oil lube place) said he had the television that came with this but he uses it. I think he's got the remote, would just like to use it for a minute to turn the function off. It would be nice to find the original remote though. I now have 3 non working main components, this one, a JVC receiver, and an old Kenwood manual amp. No tunes in this house at the moment!

 

[EchoWars]

Take a close look at this: http://www.remotes.com/store/kenwood/a70026005.html

Not necessarilly as a replacement, but to see just what function you'd be 'turning off'. I don't know what that might be.

 

[SicMan]

Could there possibly be a "reset" button inside to put it in a normal mode? Just guessing. Maybe near the main digital circuits?

John

 

[Stormseer]

That remote might work, but looking at the original one it has buttons for options not on the pre-amp. On the pre-amp this is what's lit up (remote), and the volume level right by it is low. There is a main volume control knob on the pre-amp. I'll call about the remote, thanks for the link for it & all your help.

 

[SPL db]

What that looks like to me is the volume setting for a remote pair of speakers...
meaning a second pair, or surrounds (if the unit is surround sound capable).

I see that you're in NE... where-a-bouts are you located? I'm in Omaha myself.

Maybe I could stop by and take a look at it for you? :thmbsp:

Scott

 

[mhardy6647]

It's a preamp Scott; no speakers

The display on mine looks just like the one in the prior post, with the volume control display stuck at ca. 30% "up". Almost no output from the pre. Almost. Cranked all the way, a little sound bubbles out. The tape monitors are pass-throughs, so they work fine -- not that this helps much.

Maybe this was some sort of 'anti-theft' feature?

 

[Stormseer]

I'm in Beatrice Scott. Like mentioned we've come to acknowledge it's an anti-theft feature. Maybe anti-resaleable too. There is the pre-amp (remote) volume level, but on the pre there's also a big main volume knob. Strange system like when they wanted to get rid of vintage tube & vu meters, mix it up with digital and push buttons w/ some EQ sliders. The main amp has nothing but a power button, a couple other buttons and a lit bars to show left & right channel levels. Mrh, mine (amp) just shows the red bar in the middle fully cranked up, not a single level signal for L/R channels - I can hear, but not the bit least loud..

 

[SPL db]

It's a preamp Scott; no speakers

Well that's what I get for posting this late at night! :thmbsp:

Scott

 

[Stormseer]

Mrh - if you still have that pre-amp still, give up on the anti-theft option. You need a remote to turn the volume up on the pre. I found one on ebay for $24 & now the whole system works great. Look for a Kenwood remote control unit # RC-70. There was 2 on there last week, I was watching one then seen one for buy it now that ended up costing less. The Main Volume buttons raises the bars on the pre, now all the bubbles on the amp bounce like they should + there's