Kolster Brandes 666 Valve radio restoration.

[Gabe001]

Originally Posted by real0real

another picture as flash on previous picture made case looked marked

Looks impressive! Well done.

[Station X]

Originally Posted by real0real

Have had a look at
Both capacitors lead from R17 ,and the coupled to a resistor , from the end of the resistor 2 leads , one goes to C9 Capacitor direct ,the other lead goes to a junction then to bottom of R12 Resistor have attached picture

Clive

That makes no sense to me, I can't see why the caps would be connected like that.

Do the positive (red) ends of the capacitors go to the same end of the resistor, or opposite ends of the resistor?

What's the resistor's value?

[real0real]

Will have a look and check bit later today , have noticed from picture taken ,possibily marked on outer case with red band on capacitors if correct positive ends going to a resistor ,
(plus uploaded a pcture of old capacitors / resistors replaced)

Clive

[Station X]

The positive ends of those two capacitors are going to either end of a 3.3k resistor. One end of that resistor is terminated on a tag, or perhaps a valve holder pin. Various wires lead from that tag or pin.

Which valve and pin is it and where do the wires lead to?

[Herald1360]

That 3k3 resistor and the caps look like a later addition to the set. Most of the resistors are body tip spot types and the soldering around the 3k3 and capacitor is a bit grotty. There aren't any 2uF capacitors in the service data either.

[Station X]

Yes on all counts. I was trying to work out what the mod, which may have been incorrectly applied, was intended to do. Given the capacitance and voltage of the capacitors, additional smoothing seems likely.

I'd be amazed if the smoothing caps within the cardboard container have survived. It may be necessary to restuff it or fit new caps on tag strips, or suspended in the wiring.

[real0real]

Which valve and pin is it and where do the wires lead to?

have not had chance to look at today ,will have look at tomorrow

Clive

[ms660]

Ref, 2nd photo in Post#231: That decoupled 3.3k resistor looks to be connected in series with the HT side of the 1st IFT's primary winding, you can see that they have removed the HT supply feed (in & out) wires to that transformer from tag H and connected them to the end of the resistor, the other end of the resistor is shown heading towards tag H of the IFT, you can see the small hole that's used as a reference point to identify the tag letters, immediately to the left of it is tag G with the two wires that are connected to it which connect to the transformers primary tuning capacitor and the anode of V2, next tag clockwise from that (but out of sight under the capacitor) is tag H.

If that's any help.

Lawrence.

[Station X]

Thanks Lawrence.

I wonder have that interacts with R20, C8 and C18 then?

[ms660]

It doesn't, it's in series with the primary of the 1st IF transformer only, one of those de-coupler capacitors is connected to C18, the other's connected to tag H of the transformer.

You can see from the various photo's that the feed ultimately comes from R13 on the main tag board, it makes its way across to the 2nd IF transformer and then to the input to that 3.3k decoupling network then it makes its way across via the RF transformers E tag to the small tag board on the side of the chassis where it connects to R20, from there it connects to C18.

The original route can be seen in a photo on Mikes' website.

Lawrence.

[Station X]

So one of the new caps is in parallel with C18 then?

[ms660]

Originally Posted by Station X

So one of the new caps is in parallel with C18 then?

Yes, so far as I can make out.

The resistor is in series with the 1st IF transformer only.

Lawrence.

[real0real]

I have tried tracing where wire from capacitors and where goes to appears connected to IF L12/13 as far as i can make out attached sketch

Clive

[ms660]

According to the valve data, pin 5 is one of the heater connections.

Lawrence.

[crackle]

Lawrence must have found section A of the KB service manual which has notes on the coils and other issues. It's available up top under KB Introduction. Sometimes the small hole is very difficult to find as it can be under a component.
but here is the bit on the coils.

[ms660]

Originally Posted by crackle

Lawrence must have found section A of the KB service manual which has notes on the coils and other issues. Its available up top under KB Introduction
but here is the bit on the coils.

No, I got the coil tag info from the Trader sheet, I don't have access to section A etc of the manual.

Regarding the 3.3k resistor etc I just figured it out from the photo's, hopefully I got it right.

Lawrence.

[real0real]

Thank you to everyone thats helped on getting this radio to work

clive

[crackle]

Well done for a good job of preserving the radio, I bet it sounds good. A special well done to all those who talked you through the process.

Mike

[real0real]

Hi Mike ,
Sound quality is very good well built/made speaker

Clive

[real0real]

Hi.

Can anyone help?

Previously restored a Kolster Brands 666 Radio through forums, but this week has developed a fault., Radio sound when switched on has gone. It started making a loudish buzzing and crackling noise when switched on few days ago . switched off tried switching back on there was a crackling for few seconds, then no volume or sound. I can still hear slight crackling if I the rotate bass / tone switch ). When switched on now can here crackling for few seconds then nothing, any thoughts what maybe causing problem?

Regards

Clive