Grundig 3028 Cabinet Restore

[Geaney]

Yesterday I started looking to see if I could find a reason why the transformer was running 'hot'. Mains input after the dropper is 216v and connected to the 220v tap so all looked ok there. Voltages and currents looked within spec. I started ohming stuff and found the mains on/off switch was dodgy. When closed the resistance never went to zero and would vary from 40Ohms to to around 400Ohms when the contacts were 'jiggled'. Since it is impossible to do anything with it in situ I figured there's nothing else for it - the switch has to come out.

Getting it out was fun but I got it out in the end. I did all the spraying and cleaning I could and I got it much better but still not 100%. When closed it would go to zero Ohms but still subject to variation when the connectors were moved.

Since it is a custom switch I figured I had no choice but to re-fit it and hope for the best. As I tightened the mounting nut the switch suddenly cracked down on side and various internals flew out!

So, I'll confess to some non-seasonal expletives at that stage! Having now calmed down (the morning after) I've ordered up some switches that are similar to this one but of course the special switch lever shape will need to be replicated. Oh well - one must remain detached!

Cheers, John

[Geaney]

I managed to repair the on/off switch so it's back in action. I'm still struggling with the T/F running too hot. I've decided to hook it up to the variac and drive it directly on 220v (and take the dropper out of the primary circuit) just to see if that makes a difference.

Cheers, John

[Tedzed1]

Hello John, I have one of these I use for spares, If you need a proper switch, just let me know,
You can have it FOC, just the postage cost.

I am not sure, but I may still have the Transformer, which is a UK spec 240V type as the radio I broke was the UK spec Marlborough.
Just let me know, and I will have a look.

[standunmj]

hi john, tedzed 1's offer sounds like a good idea, except bear in mind the transformer is 240v, remember your grundig is an irish version and designed for the grid system here 220v, adding another resister into the circuit might work or[provided it has the variable voltage tappings]
if you want to go down that rd, lets know how you get on anyway,

ive got a problem with my pye p75 re the cabinet, and would be grateful for your expertese, the cabinet was badly scratched on top and i had to scrape it off , its on the forum here im wondering could i use some kind of dark wood dye to try and patch the damage to the side and top, regards maitiu.

[Geaney]

Thanks Paul,
Looks like I might be OK with the switch (so far so good). I'm going to do more testing on the T/F so I may be calling on your kind offer if the T/F itself is my main problem.
Cheers, John

[Geaney]

...........
ive got a problem with my pye p75 re the cabinet, and would be grateful for your expertese, the cabinet was badly scratched on top and i had to scrape it off , its on the forum here im wondering could i use some kind of dark wood dye to try and patch the damage to the side and top, regards maitiu.

Hi Maitiu, as a rule I prefer to colour the final finish rather than stain the wood. That way you can sand it off it if doesn't turn out right. The photo doesn't show the damaged parts but in general I'd make the wood look as good as possible then seal it and look to match the colour as the final stage.
Cheers, John

[Geaney]

.......
I am not sure, but I may still have the Transformer, which is a UK spec 240V type as the radio I broke was the UK spec Marlborough.
Just let me know, and I will have a look.

Hi Paul, well I'm in the market for a transformer so when you have a chance perhaps you could have a look and see if you still have one. If you do then I'd be happy to 'come to an arrangement' as they say. I tried various things like hooking it up to the variac and running it without the mains dropper but with the correct mains voltage - no luck. As a last resort I disconnected all outputs and it still runs hot. That and the clutch are the two big items to be finished. For the rest it's come a,long way and it sounds great.

Cheers, John

[Tedzed1]

Hello John, no problems, I will pop into the loft this week and dig it out, I will let you know when I have laid my hands on it.
Let me know if you want me to throw the switch in as well.

[Geaney]

Well there will be a short hiatus in the status of the Grundig while I sort out a replacement mains transformer and some other bits and pieces. Many thanks to tedzed1, Maitiu, Nev and other for the great help in getting it completed. The set now works and sounds great so I've moved it out of the workshop until I'm ready for the next (final?) phase of repairs. It looks and sounds great so it will definitely get plenty of use - at the moment I only listen to it for about 45mins at a time because of the T/F overheating problem.

It might be a while before the next update.

Cheers, John

[Yorkie]

A fantastic restoration of this wonderful set John - congratulations on getting to this stage, and in giving a well illustrated and documented account of progress along the way. That will be invaluable to anyone wishing to tackle a similar restoration of what is quite a complex set, posing many challenges which you've managed to overcome, both with the electrics, and not least, the cabinetry. It's very uplifting to see such a set restored to its former glory, that was not just 'on the blink' but 'on the brink' of being almost beyond redemption, and certainly beyond the inclination of many restorers to tackle such an ambitious project.