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Beomaster 1200

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Krolroger
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Krolroger posted on Fri, Dec 13 2019 3:14 PM

Hello all,

Just finishing off a BM 1200.  It needed a recap and replacement of some presets, lamps and a broken volume poti.  

I spent some time making a new cursor out of 3.5mm acrylic sheet by hand.  Filing the slim flanges at either end was tedious work and I'm looking at CNC machining sliders out cast acrylic sheet in the future as the price of DIY CNC machines has fallen rapidly.  Has anyone had a go at this?

The cast aluminium sliders and tuning slide came up well with etch primer and aluminium paint.

The waveband lamp indicator brightness is adjustable, but the stereo lamp is dim in bright light.  Is there a way to improve this short of fiddling with tuned circuits which I'm not qualified to do?


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W.Frankenberg / Gandalf
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Krolroger:

I spent some time making a new cursor out of 3.5mm acrylic sheet by hand.  Filing the slim flanges at either end was tedious work and I'm looking at CNC machining sliders out cast acrylic sheet in the future as the price of DIY CNC machines has fallen rapidly.  Has anyone had a go at this?

The cast aluminium sliders and tuning slide came up well with etch primer and aluminium paint.

 

Good Work I used a cd Plastic Cover Sad

 

Krolroger:
The waveband lamp indicator brightness is adjustable, but the stereo lamp is dim in bright light.  Is there a way to improve this short of fiddling with tuned circuits which I'm not qualified to do?

the brightness for the waveband display can be set with the potentiometer 157;
but if the brightness is ok for FM, then it is the tuning of the electronics for AM and LW,
or the two lamps for AM and LW are defective or have wrong values (should be 12Volt 30mA).

 

 

 

wilfried

Dillen
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Dillen replied on Sat, Dec 14 2019 11:06 AM

The FM/SW/MW/LW (depending on version) lamps brightness reflects the received signal strength so will vary with this as you tune up and down the dial.
The Stereo lamp should be either on or off.

Martin

Krolroger
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Thanks, all.

The stereo lamp is on but only dimly.  Lamp values are all correct.

I will check out what's going on round Tr 15 and TR16 which is where the stereo indicator is switched.

solderon29
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Finding those cursor's is like searching for the holy grail?

I too have a Beomaster 1200 that's missing it's cursor slide.These were/are remarkably stylish Beomaster's.I like the later black version (BM1001)too,but they alway's seem to lose their tuning cursors too.

I'm surprised that Martin doesn't make a kit for this,prap's there is not enough demand?

It's quite a complex moulding as you know,and then there are the plastic tensioners and the little knurled wheels.

I imagine that there must be envelopes in drawers around the world,where owners have put the missing bit's when they fell off?

Have you tried replacing the stereo lamp,as they become "tired" with age,and also the plastic lens becomes cloudy too.

Not a very powerful amplifier,but nice performer.I've been toying with the idea of rigging up a muting system for the switches of mine,they are alway's noisy with these units.

Nick

 

Dillen
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Dillen replied on Sun, Dec 15 2019 10:06 AM

I have reproduced the windows for a.o. Beomaster 3000, 4000, 4400, 5000 tuner and Beolab 5000 amplifier and of course I can also make
the windows for Beomaster 1001 and 1200.
The problem with the cursors is, that, even if some cursors "merely" yellow og fog and would "just" need a new window, the majority of the cursors
gets completely lost and when they do that also the front metal bracket, the three small fingerwheels and the two nylon sliders inside is lost.

Without the guidance and control of the front bracket, the rear bracket becomes very lose and it too loses it's small slider pins.
Ideally the whole sliding cursor must be reproduced, - that's a total of ten (!) parts. Five metal, four nylon and one acryllic.
Neither of them easy or cheap.
A complete cursor would end up costing 100-120 euros - unless it can be made in large numbers (read: 500.000 pcs minimum) but I don't see the market for this.
And then the metal brackets and wheels should be made in both silver and black, just as the windows should be made with both orange and green lines.
And - to prevent fogging, yellowing and parts becoming brittle, a little UV-protection must be mixed in with the acryllic.
Not that it's a huge problem, I already do it with all the windows I make, it just has to be taken into consideration.

Almost all of the parts I provide are sold with very little profit - if any at all, and for most of the parts I will never reach breakeven - not in twenty lifetimes.
Unfortunately, Beomaster 1001 and 1200 are not top-range machines and not THAT sought after, at least not yet.
There is a demand for the parts, it's just not enough - yet.

Martin

Krolroger
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Gents,

Hence my suggestion of an entry level CNC router such as this for GBP 120:

https://www.ebay.co.uk/itm/CNC3018-PRO-DIY-CNC-Router-Kit-Engraving-Machine-GRBL-Control-3-Axis-PVC-TK-V2T8/233364263982?hash=item365598142e:m:mm8xH5-0BRW13FGs6v6dXxQ

The original cursors were injection moulded as Martin says, but 3mm cast acrylic sheet (the only suitable type for milling) can be bought for a few quid on that auction site and makes a presentable, non yellowing alternative with better clarity.

Out of interest, I got a couple of commercial quotes for machining.  The best was a unit price of GBP 12 for a run of 20.

There are freely available software packages (like Easel) that are just about adequate for this purpose.  Alternatively, many of these CNC routers can be operated offline, using buttons.

Martin, was there a SW version of this?

Simon

 

Dillen
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Dillen replied on Sun, Dec 15 2019 3:23 PM

Krolroger:

Martin, was there a SW version of this?

Yes.
Two SW bands instead of MW and LW.
Dial and knob lettering different accordingly.

Martin

solderon29
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I thought that might be the case Martin.I'm still ever optimistic of getting a left hand door hinge made for Beogram CDX,but so far quotes would entail selling the house(again!)

Your solution seems do-able Simon,for the cursor at least.If we only had an original intact cursor,praps someone like Beolover could 3d copy the bracket,springs and wheels?

Nick

Krolroger
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SW version a beautiful rare beast indeed.

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