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
Having finally completed the replacement of the body panels of my 17yr old BMW Z3 I can get back to doing the things I enjoy more.....Mr Roast dropped this off
Dave has asked me to do a recap, I will get in touch with Beolover for some of his shapeways laser printed parts, I will enquire about replacing the relay and the lamps too while it is dismantled,
Great project!
I see that the carriage pulley has already been replaced. Good!
The hardest part for me was setting up the suspension. I think I still have to find how to do it properly. No matter what I do, the platter will always sit below the top panel’s surface.
Mmm.
Jacques
Dave
Sauvignon is our poison of choice, we have several bottles of single malts that have accumulated over Christmas and birthdays etc....and although very nice we prefer more refreshing tipple ;¬)
ProGram:Hi Jacques, It is not the suspension, it is the subchassis itself. The material deformed over the decades. Now the heavy platter hangs lower than the rest. When you try to align the platter with the cabinet by the springs, the rest will bump from the underside. And when you screw up the platter bearing, the tonearm rails will be too low. I thought of taking the subchassis out and try to bend it back, but never came to that point. Chris
It is not the suspension, it is the subchassis itself. The material deformed over the decades. Now the heavy platter hangs lower than the rest. When you try to align the platter with the cabinet by the springs, the rest will bump from the underside. And when you screw up the platter bearing, the tonearm rails will be too low. I thought of taking the subchassis out and try to bend it back, but never came to that point.
Chris
Interesting! I had never thought of that.
Craig
Working on this BG is like taking a paid holiday.
I ALWAYS enjoy it, even when unexpected glitches crop up.
Menahem
Menahem....I agree, its very therapeutic.....I don't want too many glitches popping up however ;¬)
thought it wise to remove the stylus before commencing any activities
I have a shipment of parts on order from Rudi, shapeways parts...miniature relay, LED lamp replacements and so forth....so whilst I'm waiting I decided to take a look at the carriage transport switches, easy start.
When I removed them I found they are in exceptionally good condition, I was rather looking forward to gold plating them, I bought a kit of ebay thinking to do my BM6000 (both of them), looks quite easy to do and the kit was quite cheep to, don't see the point in disturbing these just to satisfy my curiosity so will put them back as is...……...
Wow, I’ve never seen that before ! Very nicely preserved example.
Good timing Craig,
I'm mentally preparing myself for restoring my 4002...
Popcorn time :-)
Moving on to the control panel the switch contacts are not as well preserved.....
As I know Rudi may be looking in on this from time to time (his package of shapeway parts,LED's and relay are now in the post) these will have to come out.....they are held in with quite a large amount of solder.
Rightly or wrongly I decided the best way to get them out was to apply the soldering iron and use my solder sucker to remove all the excess solder, then nit the sides together and pop them out.....worked fine, as can be seen quite a lot of solder needs to be sucked out.
Flip side of the board....have to say this machine is very clean.
Next will be an attempt to gold plate the contacts, they will require a clean up with 2000 grit emery first as they are a little tarnished.
First one cleaned up, de greased and acid pickled followed by the actual electro plating, whole thing took around 30 mins.
It's difficult to decide how long to keep the piece in the solution as I'm not sure how thick the plating needs to be, I have a vague memory of relay contacts being flashed with noble metals to ensure longer life, but I have no idea how many microns thick that would be.....so im going for a nice looking finish!
And another pic of the first one alongside its peers...…..
OK, this is serious work now!
Finished up the gold plating....looks better and should prevent the contacts tarnishing for some time.
Nice! Can you PM me the link to where you purchased your plating kit?
Sure....was an ebay purchase, quite good too complete with lots of information and a blow by blow description of how to carry out both pen plating and tank plating.....I did a bit of both, or rather a combination of both, just to get a feel for it.
https://www.ebay.co.uk/itm/Gold-Brush-Plating-kit-for-Jewellery-and-antique-repairs-Gold-Plating-Kit-x/253328481919?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649
Great. Thanks for the information.
Awaiting Rudi's package before I progress.....
Not quite convinced that I understand the function of the lamp that's sitting on 1PC.....I've had a look at the circuit diagram but it's not obvious, and more importantly should it be replaced? Martin......I'm looking at you ;¬)
I didn't replace it on my two Beogram 4000 turntables. The Beogram 4000 power supply takes AC from the mains transformer and converts it to DC voltages for the Beogram control circuitry. The platter motor is AC though so the Beogram 4000 has a circuit that generates the correct AC signal for 33 1/3 RPM and 45 RPM. The Beogram 4000 uses a Schmitt trigger in that circuit to generate that AC motor drive signal. The incandescent lamp is used by that trigger circuit.
The lamp is part of a Wien-bridge type oscillator, where its special resistance properties (varying with the current flow and filament temp.) are used, rather than its ability to light up.It doesn't really wear and there's usually no need to replace it.
Martin
Wien-bridge...that is the name I couldn't remember. I had Schmitt trigger stuck in my head for some reason.
I knew it had to be something cunning from the B&O boys.....talk about lateral thinking! will take a closer look
Here is a quick video of the function of the light bulb in an oscillator circuit.
Rudi's shapeway hardware has arrived, he even included the capacitors...…...
Keypad complete and can be re assembled....
Looking good Craig! Just back from a week in sunny Norfolk and excited to see the progress!
Those gold plated switch contacts really stand out don't they. Great job.
Annoyingly on re assembly I discovered that not all the switches where operating crisply, this was also experienced by Rudi on one of his many exercises...Rudi identifies this as a design fault, it may be down to wear over the years...however I have resolved the problem in the same way, a blob of epoxy resin to build up the plastic spigots causing the grief...…..
While waiting for the epoxy to go off fully I have made a start on the main PCB.....new relay fitted and the big electrolytic capacitors replaced, tantals next up along with the 33 & 45 rpm trimmers. But for now a glass of wine is called for ;¬)