Hacker RP18 Sovereign.

[Joe]

Last Saturday I bought a Hacker RP18 Sovereign from an auction house in Tonbridge Wells which arrived earlier today.

               

So far I haven't done anything beyond establish that the pair of batteries with which it came fitted are fine - they're now in the Autocrat - and that the aerial just pulls clean out, though I think I'll be able to fix that.

The only testing I've done is to establish that a signal injected into the volume control comes out of the speaker, which is more than I was expecting.

It isn't a thing to rush into fixing so I'll report more in due course.

- Joe

[Steve_P]

Clean the buttons and change the AF11x transistors.

Cheers,

Steve P.

[Mark Hennessy]

The only testing I've done is to establish that a signal injected into the volume control comes out of the speaker, which is more than I was expecting.

Me too

[Andrewausfa]

Hi Joe,

That doesn't look too bad under all the grime.

I have an RP25A which was in a similar condition to yours but not working. I traced this to the the volume control/switch which was changed to a modern part thanks to a post from Mark Hennessy which got it working. There was a wave band switching issue which was cured by a squirt of cleaner. The wiper on one of the variable resistors on the audio board must have been tarnished and wasn't making good contact with the track which was cured by adjusting it from side to side.

Lastly, it has the occasional bad day with the audio board connector. Nothing new there then!

Regards

[Joe]

After fixing the aerial earlier I thought I may as well have a proper look at this.

Firstly I would disagree with the manual that after removing the screws the chassis "May now be removed from the top without difficulty."

The major stumbling block I've encountered is de-soldering the transistors as the legs are in pipes. Neither a sucker nor braid seems to shift them and I'm starting to think that if they get much more heat put into them there'll be no point testing them. Is there some technique of which I'm unaware?

- Joe

[Mark R]

Joe DO NOT HEAT THE PIPE it will melt the board, from memory you heat the leg which goes into the pipe.

cheers Mark

[Joe]

Thanks for the tip, Mark. I'd better find my heat shunt.

I'll certainly try to keep to proper chassis and valves in future.

- Joe

[Mark Hennessy]

Joe, just put the soldering iron on the rear of the PCB and pull on the leg with long-nosed pliers from the component side - it will come out easily, with no drama. Outer pair first, then the inners. Then clean up the solder from inside the pipe with a standard de-soldering tool. Honestly, once you've done a couple, it's really very straightforward.

Mark

[Joe]

As with all things it's practise.

Well, I've done the VHF side and things didn't go too badly, I suppose. The first two transistors were dead-short screen to emitter and and had a lesser short to their collectors. The other two seemed fine.

Unfortunately (here it comes!) the leads had got badly mangled and while straightening them one of the bases broke off right at the top. I've put a BC327 (which work in R200s) in but it's not doing anything: there's no sound at all coming out of either it's own amplifier or my external one. I wasn't expecting it to WORK with the wrong transistor but thought there may be some hiss or oscillation at least. I haven't got any AF114s but should be able to borrow an AF117 from something else. On the external amp it's drawing 10mA on VHF and 5mA on MW and LW.

I'll have a go at the AM side tomorrow with Dr Mark's method and see if I can get that going as if not it implies that the switchery is at fault; I have noticed that the "Quiet Tuning" button doesn't lock down. Should it? I'm also suspicious as there's no crackling when changing wave-band. In the mean-time I'll study the circuit a bit more and try to fathom what does what.

Cheers

Joe

[Mark Hennessy]

The QT button doesn't latch. It reduces the gain of the FM IF amp (and disables the AFC) so that you can find the centre peak.

Have you an audio oscillator so you can inject a signal at the top of the volume control?