Introduction and a Clansman 320 problem

[Briggs 55]

Hello,

New to the forum so an introduction may be in order. I'm a 2E0, based in Devon and I own a Clansman 320 thick finned version. In my spare time I dabble in woodland management so the 320 is a great bit of kit for outdoors, it's a hobby and also a bit of safety comms in case I miss with the chainsaw and cut through one of my limbs. (Let's hope not, eh?)

So, here's the issue with my beloved 320:

On power up it has the usual start up tones but with all frequencies correctly dialled in, when I try to tune the antenna, I get a solid tone and a full needle deflection. A full deflection would normally be great but it's not tuning up and when switched to low power or high power there's no needle deflection. The PTT appears to be clicking on for transmit inside the radio. I've checked batteries. I've tried it on the whip and long wire. It makes no difference so I'm guessing it's something inside that my basic fault finding can't test or fix.

I have no problem sending it of if someone can recommend a reputable Clansman repairer.

Thank you in advance, I hope someone can help me before I go down the FT817 route...

Briggs.

[G3VKM_Roger]

Hi there and welcome to the group. I'm sure you will find some other PRC-320 owners who will advise you on the problem you have but I'd like to mention that there is a dedicated group on Yahoo for the 320 and other Clansman sets, you will find the group info on:-

https://groups.yahoo.com/neo/groups/prc320/info

I do own a 320 but haven't had much experience with using it yet, so I'll let more knowledgeable people advise you!

73

Roger/G3VKM

PS; You could try http://www.ptsnorfolk.co.uk/ for repairs, I bought most of my gear from them.

[ex seismic]

Does it receive OK? A good test is VOLMET on 5.452 (Clansman dial frequency)? If not, check the co-ax link, they can be faulty inside. Also does the set rattle if you shake it? 320s are well know for having loose fasteners inside, even if it doesn't rattle. I've just had one of mine apart to fix a power unit problem and found all the aerial (hint hint!) connections were only finger tight.
Can you run it into a dummy load, if that test is good then it is an aerial tuner issue.

Gordon
G7KNS

[Briggs 55]

Okay, I will try those possible solutions. Failing that, I made contact with PTS as a back up.

Thank you.

[G6Tanuki]

PRC320s can get distinctly wobbly if they're fed from unstable/high-series-resistance DC supplies - I'd suggest you make sure yours is getting at least 22V at the radio's DC input when in 'key-down' service.

Equally - the various voltage-regulators [module-5 inside the radio] are well known for issues with the inverter and the 1970s-spec tantalum capacitors associated with the +130V regulated supply that feeds the synthesizer. If this goes wobbly because the capacitors are leaky, it doesn't regulate and then the synth won't lock.

See http://www.vmarsmanuals.co.uk/newsle.../prc320psu.pdf

Be aware that there are at least 2 designs of the "PSU Module" - I've got one here which is the classic as-described-in-the-EMERs design with metal-cased TO5-style ICs and another undocumented variant which has all the integrated-circuits implemented as 6- or 8-pin DIL plastic-encapsulated versions.

[Martin G7MRV]

Have you previously had any contacts using the 320? I ask because if you havent, and are new to SSB operation, you may not be aware that you will not get a full needle deflection on transmit, in fact, expect it to just jump up from the zero on voice peaks.

The previous posts have some very good advice - the yahoo group would be (and has been!) my first port of call.

You should get a tone when you key up in the ANT position, but adjusting the tuner should of course cause the needle to vary