Hello repairers

Got myself a Beomaster 3400 (quad) and there's no service manual on site. Although I do have a lot of schematics myself this one isn't there. I got those a long time ago from a repair shop. If they didn't have it they've never seen one in reality - must have been a pretty reliable one (or a rare one)

And no envelope inside - must be one of the "newer" vintage products

One of the power amplifier seems to be gone (both transistors blown). Obviously someone was there inside before me as one of the stages has TIP141/146, the other three TIP120/125 pairs. What was the original one? The 120/125, I suppose... As long as it's the output stage only I might get along by myself, but it's a lot easier with the original schematics.

No further checking done yet; mechanically this is tricky - most of the other receivers have disassemble instructions on the bottom. This one doesn't. But it has the "bonnet hood" mechanics inside. That was quality back then

Thanks in advance,

   Gunther

Try the service manual for Beomaster 2000, it's very similar. At least mechanically

Mika,

thanks for the thought. Had a look myself already but it seems to be different as far as I can see up to now.

The BM2000 has the TIP141/146 combo - and there are 2 versions of the power amplifier

This BM3400 was dead as could be with both primary fuses blown. Meanwhile I have it running with all the bulbs refitted as it showed no sign of life even after changing the fuses (and removing the fried TIPs). Without the scale bulb all the others seem to do nothing.

The right front channel plays FM ok now, the station pots had their wheels loosened and didn't turn the spindle etc.

And the wooden housing is broken into 3 parts...

It'll be a long way to go, but that's where the fun is

   Gunther

This is not going to be a repair guide - can't compete with Soren / Rich / Ev / Martin / Bogener's etc.

But reading the operating manual gave back life to the rear channels immediately ... by pressing "Stereo" - how about RTFM

    Gunther

hemenex:

This is not going to be a repair guide - can't compete with Soren / Rich / Ev / Martin / Bogener's etc.

But reading the operating manual gave back life to the rear channels immediately ... by pressing "Stereo" - how about RTFM

    Gunther

A pic or 2 will do

Søren Mexico:

A pic or 2 will do

If there's nothing more....

You can see the 141/146 to the left, in the middle the removed fried ones (120/125), to the right the 120/125 pair that's still ok.

Now not knowing if I should use the 120'/125 or the 141/146. Probably both will do (and I have more 120/125 than from the others). Now that I have 3 out of 4 running maybe it will be repairing by comparing

Anyway - a manual would help. Or maybe I have to ask someone in Struer next May to dig into their archive...

  Gunther

Hemenex,

Send me your email, and your BM3400's Serial number (there were 2 versions) I'll scan my original Service Manual for you.

Regards

Menahem

Hello Menahem,

helpful as ever

PM sent. hope it gets through as I've had problems with the IE before. Firefox seems to work though.

Thanks alot,

   Gunther

P.S. Fourth channel working, comparing with the other three worked out fine. Used the TIP120/125. And there has been another one in this machine before for sure - a lot of transistors in the pre-stages were different in the 4 channels And if you have a close look at the transistor just below the pot - that one had a crack in the housing. And one of the 4148 was blown as well as the 10R resistor...

Manual sent - let me know that you got it OK.

Menahem

yep, thanks again...

can't compete with your BM3400, though. Mine has to do with a little cleaning, glueing the wood together and lettin' it run for some days...

No real quadrophonic sources available

Have you ever tried out the matrix decoder?

   Gunther

P.S. Problem solved, case closed

You can use the CD4 Din5 input at the rear for any line-level source - I use mine for a CD. That leaves the Tape inputs for Tape and VCR - you can play with the front and rear inputs, and the Stereo button to get whatever you want on all 4 speakers, or 2 at a time.

Over the last 10 years, I have restored 3 BG6000 quads, but each time I demonstrated it,  the customer took it away. So I am waiting to find another one. In the meantime, I'll be very happy with my "new" BG4000. I still have a large selection of CD4 and SQ Martix LP's.

The (SQ) Matrix is very nice if you have 4 speakers, and a Matrix LP. Matrix LP's can be played on a stereo turntable. Unlike the CD4, the SQ decoding is done inside the BM3400. Playing a regular Stereo LP with the Matrix button depressed is a matter of taste. Some I like Matrix, some I prefer with regular stereo.

Also, try playing an LP with no buttons (not even the Stereo button) depressed at all (except the Phono) - that is pure unprocessed sound, as it comes off the stylus.

I like this best of all.

BTW: @ Søren:

#2:

   Gunther

Menahem,

Is there a special marking on those CD4- od SQ-Vinyls like "CD4" or "SD"?

I do have several LP's left over from my youth but back then I didn't recognize (or better: accept)  the short quadro hype.

  Gunther

Here is a picture of 4 of my LP's - encircled in color.

The top 2 are CD4 - RCA Quadradisc, Project3 QD

The bottom 2 are SQ - Project3 SQ and SD

Those are the most common markings.

JVC used "CD" (ha-ha - a sign of things to come) or "CD4".