Pye P170BQ wavechange switch

[paulsherwin]

I'm in the process of restoring, or at least repairing, a Pye P170BQ which arrived as a wreck ages ago. The only reason I'm bothering with it is that this model was my mother's kitchen radio in the early 60s so I'd like a working one for nostalgic reasons.

There are lots of problems to sort out, but the most pressing one is the wavechange switch. This is a horrible thing made out of paxolin and bent aluminium with a few mickey mouse contacts riveted to it. The contacts are dirty (difficult to clean) but more seriously are bent, fatigued and worn.

As I see it my options are:

1. Obtain a NOS switch. Yeah, right.
2. Fix the old switch. I can't see how this could be done reliably.
3. Adapt a more modern switch to fit. The mechanics of this would be tricky and the originality of the set would be lost (though it's a poor example anyway).
4. Hard wire the original switch to LW or MW - the drawbacks of this are obvious.

Does anybody have any opinions or suggestions?

[Boater Sam]

I have seen 3 pole slide switches, can't remember where.
Could you do a mechanical fudge with a 2 pole and a miniature 2 pole along side?

[paulsherwin]

The 3 poles aren't a problem, I have a junk box full of scavenged 3 pole sliders. The difficulty is in fitting a completely different switch so that it operates using the existing slider control. That's probably what I'll finish up trying to do, but I'm not looking forward to it.

[Biggles]

Not having seen the switch in question, but is it possible to etch a small PCB with lands to match up with some kind of mechanical contacts attached to the original switch lever?
Alan.

[paulsherwin]

The service data does!'t show the switch in a meaningful way. I'll post a few pics tomorrow if I can persuade the camera's macro mode to work.

[Herald1360]

If you can't get macro to work, try standing well back and using telephoto!


Can be surprisingly effective at overcoming autofocus limitations.

Edit: If you get some decent pics, the RM entry for the set is pretty thin....

(Tried looking there to see if it would be any help)

[Leon Crampin]

Find a small 4 pole change over relay with the same coil voltage as the radio's battery. (If necessary, take advantage of improved battery technology and make room for the relay by fitting a smaller battery). Arrange for the relay to be energised on the less used waveband. Also consider an "economy" circuit in which the relay coil current is reduced once it pulls in - the holding current can be about 20% of the pull-in current, so it's worth doing on a battery radio.

Find some workable contacts on the existing switch (you only need one) to control your relay, if necessary, paralleling worn contacts. The set will then operate as designed without external cosmetic changes.

Leon.

[Biggles]

PIN diode switching, using Leon's original idea? Maybe a bit complex to engineer. Originality out of the window too.

[ms660]

There's some small 3pole CO toggle jobs here ?:

https://www.esr.co.uk/electronics/sw...-miniature.htm

Lawrence.

[paulsherwin]

Here are some pics as promised. The first three show the switch from various angles. The last two show the internal chassis which holds the tuning cap and PCB. My current intention is to remove the existing switch and attach a new one to the chassis, connected to the PCB by short flying leads. If anybody can think of a better solution then please feel free to say so.

[vinrads]

Surly it would be better and easier to repair the existing one, it's not too small to handle, cannibalize an old switch for the contacts. Mick.

[paulsherwin]

The contacts are dual sided and riveted onto the paxolin base. The idea is that they grip the sliding bits of metal on the upper bit of paxolin on both sides. This was never a good arrangement even when new, and over time the contacts have been bent and distorted by the sliding bits of metal failing to engage properly (the tolerances are very loose). They have also suffered some stiffening and metal fatigue.

As I said at the start of the thread, the contacts are probably repairable, but not by someone with my level of metalworking expertise.

[vinrads]

If you send me the switch Paul I am sure I can do something with it , all in the cause of nostalgia you understand I suffer from it myself , let me know , Mick.

[vinrads]

I take it that's a no then !