Hacker Hunter RP38A service manual

[Boulevardier]

Those original Hacker skeleton pots don't age well either. The pot I removed from an A205 board literally came to bits in my fingers when I removed it. One of the legs had corroded badly, and it just broke away from the main body of the pot before I even got it out of the PCB.
Are you saying that it was all the pot's fault, and problem now solved?

Mike

[PaulR]

I have one of those relatively cheap Duratool electric suckers which seems fairly gentle on the tracks - it sometimes doesn't remove every trace of the old solder which was a problem with one of the transistors I replaced,

I wish I could say that it was all the pot's fault, Mike. It certainly stopped me from getting a reliable standing current and proved to have an intermittent contact with the carbon track but I am not sure it was all the problem. Ironically the original one which adjusts the mid point voltage is useable but I have sent off for replacements for them both.

It's amazing that something do relatively simple as this amp board could cause so much of a problem. I can't help thinking about the reducing input voltage. I did think that the sound was becoming more distorted and fading when I first tried the set but I didn't leave it on for very long as there was a definite distortion at lower volume settings. If that is still a problem I will try Jerry's idea of using a separate power supply to test it

[cathoderay57]

Mine led me a merry dance for several days. Eventually replacing the AC176 output transistor fixed it https://vintage-radio.net/forum/showthread.php?t=156686 . These sets are worth persevering with because once fixed they do produce a nice sound, bigger than its boots. No sets of this era are much fun to work on but I think Hacker has the edge over Roberts in build quality and doesn't use the pesky Mullard Oscillator/IF modules that are so joyous to remove and dismantle.... Give me a valve set any day! Jerry

[Sideband]

Originally Posted by PaulR

there was a definite distortion at lower volume settings. If that is still a problem I will try Jerry's idea of using a separate power supply to test it

You should also exonerate the speaker! Distortion at low volume can be caused by a rubbing speaker cone (as already suggested in post #4 above).

[Hybrid tellies]

I repaired my Hacker Hunter RP38A a few years back. Apart from a few battery issues it has been working well ever since. I think my write up is on here somewhere.

Most of the audio output problems on most Hackers is down to either electrolytic caps and the presets changing value or crumbling, then setting up as per manual generally clears most problems..

These Hacker radios are built so well, great to work on sound just awesome for their size and the radio performance on all wavebands is also very impressive. I live in an area where the reception of the national FM stations is challenging to put it mildly but on this radio no problem especially if the batteries are good and the supply line is near 18v. Once the batteries start to drop down to 15-16v the RF and AF performance does drop away including poor sensitivity, lower volume levels and not so good audio quality.

[PaulR]

Thanks Simon. I have replaced most of the electrolytics whilst waiting for the new presets. There isn't a lot more to go wrong with it as I have replaced the lockfit transistors. Hopefully the new presets will work wonders!