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 am a new member to this site but I've been reading voraciously as a guest for several weeks now, ever since acquiring a cosmetically nice but inoperative BeoMaster 4000. I would like to bring it back to life and use it in a system in my sculpting studio. It was given to me and I'm told that the 4000 is a very nice unit which produces quality sound. My hands-on experience with repairing audio gear is fairly minimal but I am somewhat familiar with component design and electrical terminology. I am very interested in becoming proficient in the restoration and maintenance of older gear. I am running some vintage stuff now and am good with the fine work required for work like the 4000 will need. I am in the process of putting together a "bench" and the proper starter tools and devices. I hope that I can get some technical help with the diagnosis and repair process from the talent and experience on this site. Here is the primary issue. The amp. will not light up. I know nothing about the history of the 4000 except that it blew its main fuse and the old owner boxed it. Now when I plug in I get no illumination. I do get a faint chirping from the transformer box at roughly 3 to 4 second intervals. The signal indicator bounces about 1/5 of the way up the dial as the chirp occurs and the lamp which shares the power strip with the amp. blinks with each chirp. I ran the amp and listened and looked with covers off for 3 minutes and main fuse blows. Repeated with new 5 amp fuse and same result. Nothing gets hot, nothing looks fried inside. I did notice that the covers had been off because the cover screws were a bit worn. I currently have only an analog multi-tester and a continuity tester. More stuff to come. Any procedural and diagnostic help would be appreciated, as well as recommendations re; the standard rebuild procedure and parts required. I plan on going slowly and being thorough. Thanks again.
Hi, welcome to Beoworld. The Beomaster 4000 is a very nice receiver. As often with those vintage units, it is time for some restoration. Here is a thread from the old Beoworld forum where Beoworld member Søren had a nice Beomaster 4000 restoration project. I have also restored one. Martin (Beoworld member Dillen) can provide you with a restoration kit (capacitors and trimmers I believe). The Beomaster receivers are very compact so I recommend lots of pictures before you take apart and desolder wires so you will know how to put everything back. One problem with some BM4000 units is vibration and hum in the transformer. It doesn't sound like yours is exhibiting that behavior so that is good. Don't keep powering on the receiver and popping fuses until you get the problem diagnosed and repaired. For vintage equipment like that it is useful to build and use a "Dim Bulb" tester to prevent fuses blowing by shorts to ground. I'm sure there will be plenty of help offered by Beoworld people that post on the Workbench area.
sonavor
Here is another archived Beoworld thread where I was working on a Beomaster 4000. It was an early project for me and this thread has a picture of my Dim Bulb tester.
Sonavor, Thank you for your response. I'll google search, become familiar with and build a "Dim Bulb" tester. Pictures and videos of the unit is a very good suggestion. Compact and crowded for sure. I think that this amps a very pretty design and I get the feeling that B+O pays a lot of attention to their formal designs.
Again, thanks.
You're welcome. For some reason some of the images are no longer rendering on those archived forum threads. I did check my BM4000 thread and the pictures of the Dim Bulb tester and schematic are still there. My tester included a voltmeter, ammeter and variac though. You can build a simpler Dim Bulb tester without a variac or measurement meters for the purpose of just protecting the unit under test. The light bulb just draws the current if the unit being tested has a short to ground. If the bulb remains dim or off, then there is no short. If it illuminates brightly then there is a short somewhere.sonavor
Sonavor, Thank you. I read the entire thread and it is very helpful. I think I understand the dim bulb device and I will build on without the variac. The protection is well worth the effort. I'm still puzzled about the no illumination and no power-up situation. The transformer chirping is the only thing I've got to go on so far. I guess I'll go in and start getting some measurements but I'm definitely going to need some insights, hopefully from someone at Beoworld. Thanks again for the help.
It sounds like your problems begin in the Beomaster power supply. I would disconnect or remove the transformer to test it unloaded and see if it has problems. Probably disconnecting it would be easier and better at this point. I remember removing mine and a lot of disassembly was required due to the compact nature of the receiver chassis. You have a Beomaster 4000 Service Manual and schematic to work from, right?
Sonavor, Again thanks. I have the schematic which is in the envelope inside the top cover. I don't yet have the service manual but am in the process of tracking one down. You are so right about the "compactness" of the chassis, but I think I will do as you suggest and remove the transformer. Is there any kind of relay or switch in the transformer box which would account for the clicking/chirping I hear at intervals with power on? Sonavor, where are you in the world? It is great that members and participants on this site live all over the planet. Cheers...
I recommend you to get the service manual, it is available onsite for silver and gold members, for a small yearly fee you get manuals for nearly all vintage B&O ever made.
As for checking your transformer: Desolder the wires coming from the 47V and 22V supply. The 22V wires going to the PCB, the 47V going to the small PCB where the big rectifier is located. with the correct fuses in place connect with dimbulb tester if OK, check the supplies. This way you can leave the transformer in place.
I recommend doing an all out repair, Change all electrolytic caps, lamps, bad trimmers, small transistors in the end amp, rectifiers. And check all diodes, desolder and check output transistors,
Caps and lamp kit is available from Martin, he also supply transistors and trimmers needed.
Collecting Vintage B&O is not a hobby, its a lifestyle.
KineticsPHD: Sonavor, where are you in the world? It is great that members and participants on this site live all over the planet. Cheers...
Sonavor, where are you in the world? It is great that members and participants on this site live all over the planet. Cheers...
I am located in Texas, USA and yes, you will find help on this forum from all over the world. The Beovirus is that powerful.sonavor
Sonavor, Could you please tell me how to get in touch with Martin, aka Dillen. I would like to order the repair kit that he offers. I know that he is a member of BeoWorld but I'm not sure of the protocols on the site for the sale of parts etc. Thank you.
Sure, go to his Beoworld user link - Dillen, and use the "Start a Conversation" link on that page to send a message to Martin. Tell him you are restoring a Beomaster 4400 and ask him what type of kits he has available.
sonavor: Sure, go to his Beoworld user link - Dillen, and use the "Start a Conversation" link on that page to send a message to Martin. Tell him you are restoring a Beomaster 4400 4000 and ask him what type of kits he has available. sonavor
Sure, go to his Beoworld user link - Dillen, and use the "Start a Conversation" link on that page to send a message to Martin. Tell him you are restoring a Beomaster 4400 4000 and ask him what type of kits he has available.
Fixed that for ya. Apparently you, Soren and others have 4400 on the brain....
haha....that's right. I put 4400 by default. Thanks for correcting that for me.