ARCHIVED FORUM -- March 2012 to February 2022READ ONLY FORUM
This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022
I don't know whether to laugh or cry.
Broken switch missing spring
An odd collection of screws to hold the top chassis
I found the missing screw
Cardboard to shim and protect
They attempted to repair the illumination panel
Because they broke it trying to most likely replace the lamps. The solution was to glue the lamp covers onto the board then caulk the board back onto the chassis.
not sure what that trimmer is suppose to do.
More broken stuff
The preamp section with random replacemtn capacitors and a cardboard support for the control section. The randomly placed new capacitors are all 100V Jamecons.
Blown fuses - missing cover
The regulator is grounded against the transformer box - very nicely done !
“Prophet!” said I, “thing of evil!—prophet still, if bird or devil!—Whether Tempter sent, or whether tempest tossed thee here ashore,Desolate yet all undaunted, on this desert land enchanted—On this home by Horror haunted—tell me truly, I implore—Is there—is there balm in Gilead?—tell me—tell me, I implore!”Quoth the Raven “Nevermore.”
Did Edgar Allen Poe see this too?
Pretty sure I would have laughed before I sent it to Bennie.
Are you going to fix all that?
Rich: Pretty sure I would have laughed before I sent it to Bennie. Are you going to fix all that?
Yes - at least I hope so. But it will take some time. I keep finding more silly stuff. The overall condition is a bit worse than the Beomaster 2000 I had to piece back together back in 2011.
The electronics may be a different story. Wont know until i start messing with all that..
There is nothing we cannot do, its just a matter of finding out how (and when) Just dig in Richard.
Collecting Vintage B&O is not a hobby, its a lifestyle.
Søren Mexico: There is nothing we cannot do, its just a matter of finding out how (and when) Just dig in Richard.
This weekend will be spent cleaning and putting the broken chassis back together and repairing the illumination panel. The elctronics inside are very similar to the Beomaster 2000, so I am willing to guess the lamp values would be the same 12V 30Ma. I have those lamps already. When I replaced the bulbs on the Tantasaurus 2000 instead of buying only the 4 I needed I splurged and bought the whole box of 10.
Not sure if there was ever a dedicated service manual for this amp, instead they included a supplement for it in some of the Beomaster 2000 service manuals. I found one and bought it. so hopefully when it arrives it will have that supplement. A good electrical diagram the electrical adjustments plus the list of component parts would be really nice.
Last weekend was spent doing nothing to the 3400. I was a little under the weather and since the masnual would be here this week I decided to wait. The manual came yesterday and so today I had a look
the supplement was there - all of it - as far as I can tell about 11 pages.
First thing i wanted to know was why this ?
I am still baffled. why would this have been done. Unless I hear otherwise from someone who has worked on one of these I will be changing it back.
and finally the lamps
My next step is to inventory caps including the tants and following Mikas' suggestion from my previous thread on the Beomaster 2000 I will replace the electrolytic and tantalum caps with High temp 105C electrolytic. I have some Fujicon RK series or I can do a spec order from Mouser.
I need to order some stuff anyways Trimmers other caps for a later project etc. I recall seeing some Panasonic 105C caps a few weeks ago when I was browsing but I already forgot which ones F series maybe.
What if it's a typo in the manual?It's usually a good idea to trust what's in the Beomaster rather than the manual- Or it could simply be a wrong servicemanual:R2 is 2,7K in some Beomasters - and C2 is removed.Why do you want to change it if you don't know what it is doing?
Martin
I have that drawing as well. Neither show it as a partly connected trimmer. It also looks modern - not original.
Perhaps it was made adjustable for a reason.
I reconstructed the broken chassis and replaced the all the lamps including the the obviously incorrect ones. No - I do not trust a lot of what is inside this Beomaster.
I then cleaned the insides and pulled the two blown power supply fuses. They were 3A 250V. So my guess is that because the spec fuses blew they tried to locate the problem by raising the load.
My next step is to perform power up tests. I can do this one of two ways.
!. I can do a sequential power up. Transformer, transformer + power bridge, transformenr + power bridge+ tuner, etc etc. inorder to isolate any faulted areas. or
2. I can put a copper tube in and wait for the smoke.
Isolated the transformer installed two new 1.6A fuses and turned it on for the first test.
Failed to make contact at the switch.
So I unplugged then pulled back the preset assembly and had a look. The switch was all black and grimey and covered in some oily film. So I cleaned it and cleaned it and cleaned it using Contact 60 , ISP and Q-tips. I had to play with the contact prongs a bit so that I would make proper contact and I now have power.
I am about halfway thru the sequence of tests and the fuses have held. Transformer, tuner , load bridge are ok. What reamais is the load power. Then rolling one by one thru each channel.
A lot of un-soldering then re-soldering.
Solder on, starts to get interesting
The set held power up until I made my first load connection. I had disconnected the 5 red (positive) load wires and the 5 blue (negative) wires.
I did test the load caps at that point and it held
I then connected the first two wires the center feed wire on board 7 and the 26v blue wire on board 5. It held power for a few seconds and then blew the fuses.
I diconnect the blue wire from board 5 and retry. Blew the fuses straight away.
I then disconnect the red wire from board 7 and reconnect the blue wire to board 5 . The power holds.
I take my EVB/ESR meter and check both load caps. 5000uf at 35V should read about .05. The cap feeding the blue wires was around .06 -.07. The other cap feeding the red wires was .13 -.14.
I also checked the two 100 ohm resistors and they seem OK.
It would appear the mystery trimmer may be part of the circuit somehow.
Thsi is where it all blows - the 4 channels are still disconnected.
The is how the load caps are wired.
Took a break thought about it a bit then went out and bought some more fuses.
So today I leaves the input voltage disconnected and decide to roll thru the output stages one by one.
RF 0k the circuit holds
LF blows fuses
RR blows fuses
LR blows fuses
I will look for a root cause elsewhere, preamp control board but I am beginning to think scorched earth. I could try replacing the trimpots first but I have some doubt that will resolve anything.
You guys have so much more patience than me. Can one buy it somewhere, or perhaps there's a pill?
Rich: You guys have so much more patience than me. Can one buy it somewhere, or perhaps there's a pill?
It has taken 55 years to acquire mine. 10 years ago I would have either chucked it or I would be already replacing everything.
I guess right now I am trying to figure out why I have 3 blown channels. The no load resistors look good and test good. I am beginning to wonder if the speaker wiring didnt get crossed or something like that.
but I guess it does not really matter, I will be replacing most of it soon enough.