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
Been a while since I have had the time or inclination to come here but have missed this place!I have had 4 gram 4000's recently, one of them was a little terror :-(
Is it really worth stripping the bearings? It can be!!! Also there is no other way to access the ball races, I doubt even oil will get to them where they are placed... So give them some exercise as they have been operating over the same limited single figure range in degrees for the last 30-odd years....
The leaf switches get badly oxidised, gradually higher resistance and thus the operator has to press the keys harder, this bends both the leaf switches and the bronze springs under the keypad resulting in keys that don't sit straight. It is far worse with the 4002/4 6k decks where in the worse scenarios the keys can get creased :(
It is amazing how the servo motors respond to some TLC. As long as the brushes are in relatively good condition (the brushes can be very carefully cleaned if in good condition, but eventually wear through the fine leaf brushes) they can go from horrible noisy vibrating things to near absolute silence. When you get the motor right they have a surprising low starting voltage of 0.3V (300mV!!!) and a little bit of torque at that too!!! Utterly amazing motors!!!!
After a (very careful) clean, it is clear the brushes are fairly worn on this motor. It is not going to last another 30 years that is for sure! Exact replacements are available, but not cheap!!!I might do a writeup of a 400x restoration if anyone would like, but to be honest I do struggle with the kids and getting through work sometimes!!!
One little thing I do here is an LED mod to the speed indicators. Only because I think the original lamps are very dim. However, I can see why B&O made them dim, as too bright detracts heavily from the clean lines of the deck. However the right led with resistor produces a good compromise that is not too bright nor dim. Incandescents everywhere else though :)
Olly
What is this motor Olly?
I'd like to find a first generation bearing like this one. My 4000 has a later bearing of inferior construction, with only one brass bearing at the top and a pierced teflon auto-centering bottom thrust bearing.
How are you then? We have been missing you!
Jacques
Hi Jacques, not too bad thank you. Had a bit of a period where I didn't want to do anything, that includes B&O but I am spending more and more time underground where I am happiest lol - I can see the light again regarding my work bench so headed back to full steam now!...
The motor above is the servo, tbh we have discussed before but I like to push how much difference it can make when given some attention. I didn't mention the bath in heated oil which does wonders for the bearings :) However one false or careless move and they are easily wrecked too!!!Yes regarding the platter bearings I have not really seen a larger single bearing design in a 4000, I have a 4002 with a heavy platter I must check what bearing that has bear with me...I hope things are well with yourself and your wife Jacques..?
Olly,
Your BG4000 is different to mine.
I've had a bad time with those keyboard switches - completely unreliable, and caused 2 transistors on the main PCB to burn out. I don't have a solution for that, so it's sitting idle in parts right now.
For your bearing brushes, contact BSS www.steelstrip.co.uk, and see if they can help you. They are very creative, and have solved some interesting problems for me in the past.
I did the LED mod on both the white scale lights and red speed indicators - the details are here in a previous post of mine. Just be sure to confirm on your actual PCB whether the white scale lamps are wired in parallel or series - there were 2 versions made.
Menahem
Hi Olly,
I would appreciate seeing a 400x restoration write up from you. The more information on these the better. Can't have enough pictures either.
Thanks,sonavor
Step1:I might do a writeup of a 400x restoration if anyone would like, but to be honest I do struggle with the kids and getting through work sometimes!!!
I for my part would find a writeup interesting, your explanations are so clear that even I can understand them, good to see you again here, so keep them coming, and take your time, we wont go away.
Collecting Vintage B&O is not a hobby, its a lifestyle.
Thanks Menahem, I will check them out as I think the brushes are the weak point and this will be THE future issue with this whole series of decks I am sure. I normally replace the lamps with similar items mostly to maintain originality, but with the speed indicators IMO the improvement far out-ways this. I guess it is personal opinion on what is best :)What was your issue with the leaf switches? I find a good straightening, clean and a protective switch contact lube does the job normally, I can't really speak long term although I should think it will be a good deal of time before they deteriorate again!I increase switch sensitivity on the 6/400x decks (and master 6000) by putting spacers under the switches as per Geoff's post. Takes a while to get right but results in near feather-light controls and as a result far less wear to the pad surfaces.
Thanks for the kind words folks, I will try to do that in the near future :)
sonavor: Hi Olly, I would appreciate seeing a 400x restoration write up from you. The more information on these the better. Can't have enough pictures either. Thanks,sonavor
Søren Mexico: Step1:I might do a writeup of a 400x restoration if anyone would like, but to be honest I do struggle with the kids and getting through work sometimes!!! I for my part would find a writeup interesting, your explanations are so clear that even I can understand them, good to see you again here, so keep them coming, and take your time, we wont go away.
Step1: What was your issue with the leaf switches? I find a good straightening, clean and a protective switch contact lube does the job normally, I can't really speak long term although I should think it will be a good deal of time before they deteriorate again!I increase switch sensitivity on the 6/400x decks (and master 6000) by putting spacers under the switches as per Geoff's post. Takes a while to get right but results in near feather-light controls and as a result far less wear to the pad surfaces.
What was your issue with the leaf switches? I find a good straightening, clean and a protective switch contact lube does the job normally, I can't really speak long term although I should think it will be a good deal of time before they deteriorate again!I increase switch sensitivity on the 6/400x decks (and master 6000) by putting spacers under the switches as per Geoff's post. Takes a while to get right but results in near feather-light controls and as a result far less wear to the pad surfaces.
Straightened, cleaned and shined, generous contact lube - we must have gone to the same tech school ;-), and put spacers underneath. But one of them at the center bottom which is a 3-way (IIRC) Momentary-Closed / Normally-Open / Momentary-Closed arrangement lost its rigidity at the 90-degree bend, and was making random intermittent contact when it shouldn't have been, and that, in conjunction with the normal position of another switch, instantly generated the frying of 2 transistors.
I confirmed that - I replaced the transistors and soldered thin wires to that "switch" then onto my DMM; and bingo, during the middle of playing an LP, the famous smell started, and my DMM started beeping, indicating a short acroos the probe terminals.
Andre Hanekom in South Africa (BenSA) made up a proto PCB for his 4002 with normal common push-switches Normally-Open / Momentary-Closed. I thought of doing that for the BG4000, but that 3 way arrangement is something I have never seen in common tactile switches.
Ah yes I had one snap at the bend but I am sure I repaired it satisfactorily! Think I bent an extra tiny piece of metal piggy backed and soldered... was a fiddly job though! I find it strange that the wrong combination killed a transistor though, as often the keys are not engaged properly with the bronze springs pressing on buttons... never on the three ways though I guess....
Luverly ;) -
I'm myself guilty of liking Revox and Technics Reel2Reels (and yes I also like big wheels and reels - live with it folks ;)
- and this one is beauty, cannot wait to see the Beocord 1500 deLuxe :)
bob
chartz: How about that? Yeah, I know, not B&O. ReVox is my second passion... This is a G36 all valve recorder, half a hundredweight on the scales. No Beocord will take 10.5 cm reels I do have a Beocord 1500 deLuxe on its way...
How about that?
Yeah, I know, not B&O. ReVox is my second passion... This is a G36 all valve recorder, half a hundredweight on the scales. No Beocord will take 10.5 cm reels
I do have a Beocord 1500 deLuxe on its way...
Don't worry - be Happy
You Sir, are rotten inside out with Beo Bug and no medicine can help it.....
if anyone have one....., just please give it to him
Søren Mexico: I want one like that (Beocord), and I am absolutely convinced that I need it
I want one like that (Beocord), and I am absolutely convinced that I need it
About a year ago my uncle gave me a BeoGram 6000 for free as it was completely dead. A few days ago I finally decided to take a look at it (Reason will be explained in another thread a bit later). I opened it and checked the fuse box as the first thing. One of the fuses was disconnected but it didn't seem blown – simply just disconnected. I therefore decided to try and put a new fuse in it – And the BeoGram came to live! After that I started cleaning it a bit – there was a thick layer of dirt all over it. Take a look at the pictures:
After and before cleaning:
The red cap has to go!
The disconnected fuse:
As you can probably see on the pictures, the BeoGram still has a few things that need doing:
I have some other projects I’ll have to finish before I continue working on the BeoGram, so therefore I've assembled it again, but I’ll inform you when I start working on it again!
I didn't click the CH4-panel down again, as it takes quite some effort to dismount it, and I’m not using the BeoGram anyway until I've finished working on it.
- Dennis
Looks like a good project! I have not seen that design of RIAA board, does it have a round (valve type) base connector for inputs / outputs or a flat connector?I am sure the problems you are encountering will have been see by many here so don't be afraid to ask, but it is great fun trying to diagnose these issues yourself :)
Wow nice deck!
I hear that the RIAA preamp is one of the best ever. When in finer fettle, this should be an excellent turntable!
Nice work so far!
Step1:Looks like a good project! I have not seen that design of RIAA board, does it have a round (valve type) base connector for inputs / outputs or a flat connector?
Is this what you're asking for?:
If I remember correctly the most common issues are faulty caps and bad solder joints. Right now the only sign of life is when I press '33': 'B&O' lights up and the motor makes a quick spin. If I then move the whole tracking system a bit to the left until I can hear a click (The click comes from a small switch at the tracking mechanism), all of the buttons suddenly work. If I then press play, the arm moves all the way over the platter and back again. After that the same happens again: Only '33' works. If someone could push me in the right direction how to solve this issue, it would be very much appreciated. I'll probably let my father take a look at the BeoGram anyway - I want it to perform a smooth as possible.
chartz: Wow nice deck! I hear that the RIAA preamp is one of the best ever. When in finer fettle, this should be an excellent turntable! Nice work so far!
Thanks!
I'm definitely also going to buy a decent pickup for it! Guess a MMC20CL or MMC6000 is the one to look out for!
.
Brengen & Ophalen
I'm gonna leave the touchpanel as it is for now, as I wasn't sure what kind of lacquer to use - I then remembered, that you did the same job a few months ago, and hoped you could tell me what kind of lacquer you used. I'll probably refurbish the touchpanel when I continue working on the BeoGram - Some of the small plastic pieces also need to be glued back in place.
If the black plastic pieces are loose be very very careful removing the PCB as they have a tendency to catch and they could damage the keys. Best to slide something between the metal keys and the spacers so they cannot get caught as you slide the pcb out :)I will have to refer to the diagram to determine where to look for the fault you describe, shouldn't be a major issue though :)
Dennis: I'm gonna leave the touchpanel as it is for now, as I wasn't sure what kind of lacquer to use - I then remembered, that you did the same job a few months ago, and hoped you could tell me what kind of lacquer you used. I'll probably refurbish the touchpanel when I continue working on the BeoGram - Some of the small plastic pieces also need to be glued back in place. - Dennis
Ok Dennis just had a quick look at diagram for types 5521-25... There really shouldn't be much difference at all but maybe watch out for component markings... It sounds like when you press the start key that the base of 1ic1 (21v regulated power supply) is not receiving a signal voltage from the switch [ON], via D9 and associated resistors (voltage divider and series) including C2 and D6. As you can turn the unit on by moving the sled, so as to open switch [SO], and start then works, we know that the problem is most likely to be in one of the components mentioned above. I actually suspect it might be capacitor C2 that might have gone short or very leaky. so check this capacitor first. In fact it would be fine to remove from circuit to test; this here is designed to maintain a signal just long enough, in case you remove your finger slightly short of the sled disengaging switch SO...Good luck :)
Wow, thank you very much! I will take a look at the things you've suggested once I've finished my other projects and what else there's on my to-do list.
Thanks again!
On the BG6000, if the 45 isn't working, I'd check in 2 places - the poti on the main PCB, and the poti under the keyboard.
Thanks, Menahem. I'll take a look at it!
And thanks for your email. I've sent you a reply.
Leslie,
I think you post those photos just to make us jealous........
Leslie
You can get around this problem a couple of ways:
If you have a CD4 LP, the 4 channels go through the stylus to the amp decoder. With an oscilloscope, you can measure the output signal strength (it will be line level - approx 1.5 - 2V p-p) on each of the 4 pins on the DIN plug.
If you don't have a CD4 LP, the stylus is not going to pick up a signal for the rear 2 channels, and you will have to inject a 20KHz signal into the decoder PCB - don't ask which IC, because I don't remember ;-), but it's pretty clear on the schematic where to do it. Then use the scope as above.
SQ or other "Quad" type LP's will NOT solve your problem. It must be an LP with CD4 encoding.
You do need a contact-line / Pramanik stylus - MMC5000 or MMC6000 or SMMC20CL to decode CD4. The MMC4000 is fine for SQ types, but no good for CD4.
Does that help you?
Before cleaning After cleaning (with surgery knife)
blah-blah and photographs as needed
Leslie: Looks like your stylus has been sharpened? You did that with a knife??
Looks like your stylus has been sharpened? You did that with a knife??
Nah, seriously, I did first think it was crashed, but no. There was something like hard plastic, witch I have to remove mechanically. Maybe hard playing of some hot material has melted vinyl on it?
This proofs it pays to look things closely.
Has anyone ever opened these motors? This one is a bit stiff, so in need of cleaning/lubricationing.
I´m not in urgent need of motor, so dont need replacement, but if I ever need this could be seviced...
Leslie: Finished my CX100's and 50's refoaming and reclothing!
Finished my CX100's and 50's refoaming and reclothing!
Wow - looks great, Leslie
And I have one question: Where did you buy that 'Alu/silver look' fabric for the CX 50's?
Kind regards
Steffen
Orava: Has anyone ever opened these motors? This one is a bit stiff, so in need of cleaning/lubricationing.
Yes, quite a few of them actually.
Disassembly is rather self-explanatory. Take care when lifting off the base plate (the second one - there's another casing beneath the first one) - either first lift it 5mm and disengage the brushes through the slit, or lift out the rotor together with the base plate. Clean the brushes & commutator and lube both bearings, then it should be fine for another 20+ years.
ablaumeise: Orava: Has anyone ever opened these motors? This one is a bit stiff, so in need of cleaning/lubricationing. Yes, quite a few of them actually. Disassembly is rather self-explanatory. Take care when lifting off the base plate (the second one - there's another casing beneath the first one) - either first lift it 5mm and disengage the brushes through the slit, or lift out the rotor together with the base plate. Clean the brushes & commutator and lube both bearings, then it should be fine for another 20+ years.
Ah, ok. So it doesnt need any violence?