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Old 24th Jan 2006, 1:08 pm   #1
Sam
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Default Hacker RP38A Hunter - audio faults.

The Hunter I bought on eBay has arrived, but needs a little bit of a look-at to get it working.

There is a feint hiss from the speaker on all bands, but otherwise nothing. This hiss does not seem to be affected by the volume control, but is by the tone controls. The set occasionally breaks into a Motorboating oscillation, which is unaffected by the volume control. This effect can be started or stopped by jiggling (which is a technical term ) the five-pin connector to the Amplifier board (a type A209).

The serial-number is 58442, and there is '12 Mar 1974' stamped inside the cabinet, if this helps.

Does anyone have any suggestions where to look? The service information may help me too, if anyone has a copy.

Sam
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Old 24th Jan 2006, 4:37 pm   #2
Darren-UK
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Default Re: Hacker RP38A Hunter

Hi Sam,

The 38A is a silicon job and thus doesn't suffer the AFxxx problems. The A209 board can suffer from poor connections but as you get a hiss at the speaker the trouble is unlikely to be there - although a further fiddle in that area may prove fruitful.

The hiss and motorboating suggests one or both batteries are duff or, perhaps more significantly, the alignment has been tampered with. Check for this and look, in particular, for a loose inductor core. Another, more obvious, possibility is a dirty/fault vol pot or dirty wavechangers.
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Old 24th Jan 2006, 8:55 pm   #3
wireful3
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Default Re: Hacker RP38A Hunter

Hi Sam, I too have recently aquired a Hunter that needs some attention. The most noticeable fault is the one Darren mentioned of dirty contacts on the switch buttons. Occasionally there is no sound at all except a very faint hiss. Tapping the switch buttons restores good operation. You might have a similar problem so it is worth trying a squirt of switch cleaner before doing anything drastic.
To check the motor boating it is also worth measuring the state of the batteries on load.
I wish you success, because when working it is a very fine sounding set.
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Old 24th Jan 2006, 9:06 pm   #4
Darren-UK
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Default Re: Hacker RP38A Hunter

Further to the above and something I should have mentioned earlier; if you can restore the audio (if it does transpire to be dirty switches etc), a quick test for failing batteries and/or the cause of motorboating without using a meter is to switch to mediumwave or longwave and turn up the volume, then do the same on VHF. If there's no motorboating on M/LW but there is on VHF then it's very likely to be battery trouble. Leave the radio switched on for a couple of minutes prior though.

Last edited by Darren-UK; 10th Jul 2007 at 8:45 pm. Reason: Made briefer.
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