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
Hi all,
I'm new to this forum. I have owned a Beomaster 900RG De Luxe for around 25 years now. Unfortunately, it hasn't been used for about the last 3 years or so for one reason or another. However, since the change around in the room it's in, I now have full access to the unit, so, while I was in the house on my own tonight, I thought I would put on some vinyl and chill. Unfortunately, the Beogram 1000 record deck and the Beomaster 900 tuner/amp had other ideas. I think I have two audio issues here. These are:-
1: When the audio is playing low volume, the audio is nice, with a nice crisp bass tone to it. However, if you increase the volume to half way, the sound will 'drop out' to the beat of the bass and will get worse the louder you turn it up. I'm thinking that it could just be some dried out capacitors, but without a circuit diagram, I'm unsure where to start.
2: The second audio issue I have is with the audio balance from the record deck. The audio from the right channel is very quiet, however the audio balance from the tuner and Beocord 1500 De Luxe reel to reel deck is fine. The record deck has had a genuine B&O replacement stylus about 5 years ago.
There are other things I would like to do to it, like service the reel to reel and the record deck, but one thing at a time
Any help that somebody can give me on any of these issues will be greatly appreciated.
Regards
Mark
One thing that I forgot to mention is that the tuner amp is a replacement unit but not from a radiogram. Will this make a difference?
I replaced the original because it didn't pick up FM stations clearly. Unfortunately I never used the unit in anger after I replaced this about 3 years ago. Until now.
Welcome to the forum, first thing, as you changed the BM 900, clean the connectors mainly the phono plug and jack, and try again, if the failure is still the same, check the pre amplifier, I am not familiar with the BM 900 it may have a pre amplifier build in, or the pre amplifier is located in the BG 1000, the BG 1000 comes in both versions, with or without pre amp. These are the items I would try first.
Your have a very nice setup and it is worth the work to get it serviced and up to date, We are talking about components more than 40 years old, so you will probably have to do a complete restoration, to ensure good working units in the future, meaning: Change electrolytic capacitors, trimmers, lamps and maybe some rectifiers.
I have a BG 1000 restored, link here , I also have a Beocord 2000 RtoR, restored link here , yours is a BG 1500 but there are similarities.
I dont have a BM 900, but search the forum and you shall find, and I am sure Martin will have some comment on this.
Good luck
Collecting Vintage B&O is not a hobby, its a lifestyle.
Wow Soren,
I have just read you thread on your BG 1000 - excellent workmanship there!! Very impressive.
Mine has one more board to yours, so could this be the pre amp?
I have just read through the fault description again and I don't think I have described this correctly. I should have added in item one that this happens when using the tuner, reel to reel or the record deck.
For silver and gold members manuals and drawings are available on site, According to the service manual check the 24 V feed and the idle current adjustment. You probably have a failure in the end amps
As for the BG 1000 is the PCB equipped with a couple of transistors and some caps or is it a blank, if equipped it is a pre amp. if not it is a bridging PCB, in my BG the bridging was done with wires.
As you have a pre amp build in in your BM 900 the BG must run without pre amp.
But as you have the same failure with all 3 sources my tip is end amps.
The AD 151 transistors in the end amps. are Germanium transistors
The "correct" radio chassis will have dual volume knobs (one inside the other) rather than a balance control at the rear (out of reach in the RG cabinet).I suggest you fix the FM reception on the original cabinet - it's probably just an IF problem - that's very common.
The replacement chassis may, - or may not as Søren also points out, have a built-in RIAA module. It's either inside the radio chassis orinside the Beogram deck.If one channel is at correct volume (but the other down) the RIAA is correct.A missing Beogram channel could be caused by a bad pickup cartridge, bad connection to the cartridge, broken wire(s) insidethe tonearm (Beogram 1000s have started doing this in great numbers), broken connection inside the DIN plug that connects to theradio chassis. Plus a lot more - but these are the most common.
Martin
Hi Soren,
Thanks for this information. I will take a picture of the Beogram 1000 over the weekend and post it up here to give you a better idea if it is a bridging PCB or Pre Amp PCB.
Could you please tell me where the AD151 transistors are mounted as I have looked inside the BM900 and I can't find them.
Thanks in advance
Hi Martin,
Thanks for this information. By the "correct" radio chassis do you mean the BM900? If so, the volume control is just one knob and the balance control is at the rear of the unit. This is the same on both the original and the replacement BM900.
I did take the original unit to a couple of 'Old School' radio repairers, but they couldn't fix it, which is why I sourced this replacement from Switzerland through eBay many years ago. Could this IF problem be an easy fix?
The radio works spot on, the only issue being this 'drop out' of the audio to the bass beat when the volume is turned up. As this happens on the radio, reel to reel and the record deck I figured that the low audio on one channel from the record deck, must be a fault of the record deck.
I will make a recording of the faults over the weekend and post it, along with internal pictures of the record deck and both BM900.
Thanks for your help and advice
Check the power supply filter capacitor and the rectifier.
I haven't had chance to strip the units yet to take some pictures, but I have recorded the audio on the attached file. This audio file will give you an idea of what is happening when the audio is increased.
Excuse the quality - I did it on my phone
Has anybody listened to this yet? Anybody have any advice?
One more thing. If I sign up for the Silver membership this gives me access to the service manuals, correct? Can somebody please confirm that the service manuals are available for my units before I join?
Thanks
Manuals for the BG 1000/1500 and BM 900 are there for the BC 1500 I am not so sure, listened to the sound could be anything from bad or dirty potentiometers to caps or transistors
vivax14: Anybody have any advice?
Anybody have any advice?
I already adviced you, - what was the result?