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Success Stories If you have successfully repaired or restored a piece of equipment, why not write up what you did and post details here. Particularly if it was interesting, unusual or challenging. PLEASE DO NOT POST REQUESTS FOR HELP HERE!

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Old 19th Jul 2012, 12:15 am   #1
AD360 Rob
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Default Roberts R200 success!

Hi all,

I've just finished off my first R200, I got it quite cheaply and it looked quite forlorn but it was complete apart from two knob brights (I obtained a set, I believe it's someone here who sells them).

First of all I thought let's whack a battery on and see what happens. As expected, not a lot but some crackling on wave change and volume adjustment showed the audio stage was in with a chance. I stripped the chassis out of the case and powered up to check local oscillator, but nothing.

TR1 (AF117) was a prime suspect but no, checked out perfectly. I then did some DC checking of capacitors etc and found a couple of leaky electrolytics and resistor R22 had gone high (29 Ohms instead of 5.6) so they were all replaced. Still no LO and TR1 voltages were way off so I then bit the bullet and replaced all the electrolytics and all the coupling caps and decouplers as well.

Now the LO worked but still no output. TR3 was the culprit, a swift tap restoring operation. I changed it anyway for a brand new one I found in the garage today in a coffee jar full of transistors, diodes and an LDR, that I inherited years ago. I'd forgotten about it completely but it has some useful semiconductors inside (I know NOS AF11x can have the same trouble but I'm giving it a go). Now it was stable but rather insensitive and looked like it had been got at so a full realignment was carried out and a quick check on the output transistor bias setting showing all was well there.

Cabinet next. The grille was very dirty with a big silver stain down the front and the badge had lost most of its chrome effect finish. Grille cleaned and resprayed in gold, badge done in silver/chrome effect. The cabinet was given several washes with car upholstery cleaner and ordinary hand soap and eventually cleaned up ok. I then got hold of some red shoe polish and a couple of applications later it came up nicely. The handle does let it down a bit being discoloured and cracked but it is complete and I've heard that new ones are unobtainable now, plus a new one might show the rest of the set up!

One question though, what colour are the loudspeaker grilles supposed to be? Mine is a Series 3 set and the grille was gold when I got it and looks like it's been that way all its life although I have seen some with silver grilles.

Rob

P.S. It had two long screws through the back, they serve no other purpose than to foul the battery so I cut them down rather than have two holes. I seem to remember reading that someone else had similar screws fitted. Strange.
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Old 19th Jul 2012, 1:21 am   #2
Darren-UK
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Default Re: Roberts R200 success!

I suspect those screws were inserted by a member of the "I'm not shelling out for a PP9" brigade for the purpose of retaining a smaller battery, probably a PP3 or two in parallel. Were the proper PP9 battery snaps fitted?

On the holes, you could fill them and cover the wounds with little pieces of rexine nicked from inside the cabinet where it folds over the edges. Such a 'repair' would probably still show but would be far less obvious than the two screw heads.

The question of grille colour is a good one. I only have one R200, a very early example, and that has a goldy coloured grille - and it's gold on the parts normally hidden by the cabinet so must've been gold from new. I once had a green Mk3 example and that had a silver grille. I've just been looking at a few pictures on the internet but it's difficult to draw a definate conclusion. It seems, however, that grille colour either varied with a) the rexine colour or b) with early or later versions regardless of rexine colour.

Other members are more Robertsy than myself though, so perhaps someone will be able to state more positively.

On the matter of TR3, you've just learned a lesson I think; always suspect those transistors and have a good tappety-tap around before checking anything else . They can be little devils at times!
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Old 20th Jul 2012, 9:17 pm   #3
AD360 Rob
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Default Re: Roberts R200 success!

Thinking about it I agree Darren, those screws did look like they were for wedging up against something when the door is closed and a smaller battery is probably right. The set was fitted with its original battery snaps so I suspect a PP7. Yes, those transistors are a pain although I usually do give them a good beating first. It doesn't always work though and in this case, the oscillator transistor was fine and sprang to life after I had changed all the leaky capacitors (unusual for so many to be leaky in a transistor set too) then the second IF transistor reared its ugly head !

I too have seen a few green sets with silver grilles, some red ones too and a brown one with a gold grille. I think the gold suits the set very well and looks a little more upmarket on a red set, I wish I had done the badge gold too.

Rob
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Old 20th Jul 2012, 9:49 pm   #4
Darren-UK
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Default Re: Roberts R200 success!

Not knowing how far the screws intruded into the cabinet, I was more thinking of a PP3 or two being held between the screws, although shutting the door would be something of a hit and miss affair.

Now you mention the PP7 and snaps, that battery is a possibility I suppose. That said, why anyone would disfigure the radio to fit a PP7 when the PP9 was and still is readily available is a mystery. Any saving in the purchase price of a PP7 would be rather offset by the shorter life. We'll never know, of course, and could speculate for eternity.

Your silver badge looks fine to me. I think a gold badge would make the R200 too resembling of the more modern Roberts offerings which have a gold badge.

On those little devil transistors, I've experienced similar to yourself. I've bought radios from boot sales, antique centres etc which very obviously haven't run for years. Shove a battery in and, crackling pots aside, away they go - only for the AF11x nuisance to appear after a minute or so.
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