Well, this is probably going to be a n00b question.  Are we talking about two separate phenomena here with the B&O metal finishes:  (1) leaving oils (and other dirt and grime) behind from our fingers when we touch our equipment, and (2) an applied finish that will ultimately wear out no matter what precautions and cleaning we do?

When I look at my equipment, I can see where buttons have been pressed.  I always thought I was seeing 1 above; have I been really seeing 2?

On my Beogram 4001 (!) I sprayed the key pad with a matt paint and then with a matt lacquer. I seem top remember Beomuse doing the same - he was using silver rather than the black I used. Looks very effective!

Hi Everyone

I thought that I should provide an update to let you know how the finishing touches are progressing.  As usual, the last 5% of any project always seems to take 50% of the time and this project is no exception. 

I dismantled the Beomaster 6000 quad once again and can now claim to be able to do this in my sleep.  One must wonder how many disassembly and reassembly routines these machines are designed to take?  I am almost certain that some of my later problems are now a result of too much dismantling and this particular machine is always going to be very sensitive to that.

The first thing I noted was that one of the looms at the front had trapped the plastic wheel on the balance pot so that problem was fixed very easily.  More care was simply needed when replacing the keyboard panel.  One problem solved and six to go.

An easy problem to address was the alignment of the tuning indicator.  I tuned in one of my favourite radio stations, switched the unit off and then placed the display panel on top.  I measured the distance of the indicator from the correct mark and it was 49mm out.

The next step was to raise the tuning indicator and mark the desired position on the string with a black felt marker.  Adjusting the indicator was fairly straightforward but you need to remember that when you want to shift the marker to the left on top, it must go to the right underneath.  I messed that one up first time round.  Two problems solved and five to go.

When I removed the black display panel, the pinholes were clearly evident and these had been produced where two surfaces were being pressed hard together.  These I simply repaired using my faithful black marking pen and that worked very well.  Three problems solved and four to go.

I next wanted to work on the tuning potentiometer.  Here, I had been thinking along the lines that the pot itself was damaged but thought that I should first check the electrical aspects before wrecking the mechanical parts.

I studied the connections on the pre-set tuning board.  There are five wires at the front that supply the switched high voltage to each tuning pot – Br/W, R/W, Or/W, Y/W, Gr/W.  These should read 20+V when switched on and 0.5V when switched off.

Each preset tuning pot has three connections.  The left connection viewed from the front is the common low voltage to all pots.  The centre connection is the tuner output voltage which goes through a diode to a common output (to PC2).  The connection on the right is the switched high voltage connection.

When I switched in P5, it only recorded 5V on the high end.  Since the low end was around 6V, the variable output was fixed at 5.9V and that is why the tuner stayed locked in one position.  I next had to find out why the high voltage was so low.

The tuner voltages come from PC8 which underneath the keyboard, now conveniently parked at the front.  When I measured the resistance from the Gr/W wire on the preset to the 8TR12 collector it was clear that there was no connection.  I then traced the wire in the loom and found that it passed onto the underside of the board PC8.  Fortunately, all of the wire connections are on the left hand edge where they are reasonably accessible.  The wire had broken off on the underside of the board where it wasn’t readily visible.  Resoldering that wire fixed the tuning problem. 

Now, four problems have been solved and there are only three to go.  Unfortunately, one does tend to leave the more difficult problems for last.  I’ll report on those next time.

Regards

Geoff

You will never run out of work with a Beomaster 6000/4.
Isn't it wonderful ?  😂

Thanks for taking the time to do this thread, it's great reading and will, no doubt, come in handy for many owners and DIY'ers.

Martin

I am consistantly impressed with your work Geoff. I think you will have a nice unit at the end of the day!

Regards the switch sensitivity issue, you need to unsolder the brass contacts that look like a goalposts - you should see these when looking at the component side of the switch pcb. Gently clean the tarnished contact surfaces and your switches should work like new again.

Hi everyone

I have definitely come to the conclusion that fixing a 6000 quad is not easy and there are pitfalls everywhere.  On my last session, I wanted to lift the tuning indicator slide to access the amplifier board.  I unscrewed it, lifted it and the string snapped for no apparent reason.  It must have been chaffed and old in one area and decided to give up the ghost.

I really didn’t want to do that job but it had to be done and for starters, I have no spare string at all.  So I decided to use the second best option that has worked for me in the past and that is 0.35mm fishing nylon.  Not the best because it tends to be too elastic if the tension is not high but it is all that I have at the moment.

I normally hate doing these stringing jobs but for some reason, this one went fairly easily.  The main requirement is to have an assistant with those two extra hands – one set is not enough.  For those that might have to do this job in future, the following procedure worked well for me.

Remove all of the old string and measure the exact length if you can.  I estimated that the distance between the tips of both knots was around 166cm.

Cut 2m of suitable line and knot a small loop at one end.  This is sized to slip over the lug on the plastic wheel.

Install the plastic wheel on the tuning pot and turn fully anticlockwise.

Fold the line double and thread it up the tuning indicator and around the end pulley.  The side with the loop has to be at the front.  Use an elastic band to keep the line in place around the pulley.  This is where the extra hands start to become necessary.

Position the looped end on the left front side of the capstan and wind two turns clockwise onto the capstan.  Make sure the latest turn lies on top of the other. 

Keeping the tension around the capstan, adjust the length of the looped end so that the line can be wrapped around the wheel and the loop located over the lug.  Tension the line on the right side of the capstan and make sure that the line is located around the middle groove on the wheel.  If you don’t keep the tension during the next steps it will fall off of the lug and you have to start again.

Pass the free end around the lower of the two front pulleys and the nearest pulley at the indicator.  Next, remove the elastic band and pull it tight around the indicator end pulley.  Pass the free end around the farthest pulley at the indicator.

Hold the free end firmly and start to wind the wheel clockwise.  The coiling process should start half way down the plastic wheel and the line accumulates in the lower grooves.

When the wheel is fully clockwise, make sure that the free end of the line is around the correct pulleys and position it over the plastic wheel.  Measure the distance for the loop that will be attached to the spring. 

Make a small loop and fit the spring.  Fix the spring to the wheel and ensure that the line comes out on the very top groove.  Check that the spring has a bit of tension.  If it hasn’t, you might have to relocate the spring to a different hole or re-knot the loop.

Turn the wheel anticlockwise to pull the line in on the top groove and it should feed out at the bottom at the same time.  Test the full travel a few times and check that the tension is sufficient.

Find a favourite channel and set the indicator to the right position.  I have marked this position with a small black dot on the plastic indicator.  Slide the line over the retainer to lock the indicator ribbon in position.  I used a piece of thin card (business card) to help guide the line over the retainer and pull it through.

2133

So, there we have the newly strung tuning system.  It works and does the tuning job but I must try and source some of that proper tuning string one day.  I haven’t had much luck in finding any to date. 

Regards

Geoff

Super job Geoff. I have always wondered if a complete profession of dial cord fitters was made redundant with digital tuners. That's one job I wouldn't accept 😂

Geoff, go back to your fishing tackle supplier and ask for fishing chord, as used by fly-fishers. There are other alternatives such as Linen thread or lacing chord.

There are options out their but I am sure the nylon will be ok...

Actually, just go fishing Geoff and make sure you take a cooler of beer with you. What has impressed me most is the thouroghness of the documentation regarding this restoration. very clear and well presented.

Using this thread as a guide many of us could now take one of these Quads when we would not have prevoius.

Eugene wrote:

Actually, just go fishing Geoff and make sure you take a cooler of beer with you. What has impressed me most is the thouroghness of the documentation regarding this restoration. very clear and well presented.

Using this thread as a guide many of us could now take one of these Quads when we would not have prevoius.

 

 

Some good advice - especially regards the bear 😁 I agree with the diary entries, I try, with best intentions to do a writeup and find it hard to set aside the time to take piccies and note descriptions etc... I get into to one flow or another!