ham international jumbo not transmitting after few minutes

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davie_1977
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ham international jumbo not transmitting after few minutes

Post by davie_1977 »

Hi There Wonder If Anyone can Help Me I Have A Ham International Jumbo When Switched On For The First Minute Fine Transmits Needle Goes Up And Receiving But After Bout A Minute Speaker Goes Quiet Wont Transmit Needle Not Moving And Not Receiving Everything Else Fine Dont Know Whats Wrong
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163TM847
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Re: ham international jumbo not transmitting after few minut

Post by 163TM847 »

Im putting my money on the VCO block failing as this is a common issue.
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Ashtec
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Re: ham international jumbo not transmitting after few minut

Post by Ashtec »

I think the same as well mate ive had a few rigs with the same fault and was all down to the vco...
:D :D
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darkone
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Re: ham international jumbo not transmitting after few minut

Post by darkone »

VCO failing as folks have suggested, or AVR pass transistor failing.
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Otter
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Re: ham international jumbo not transmitting after few minut

Post by Otter »

darkone wrote: or AVR pass transistor failing.
Or a "plated through hole" near the transistor going open circuit as the transistor heats up. I've seen that.
"To this day the words Stirling bridge conjour pride in every Scotsman's heart, while to an Englishman those same words conjour literally no feelings at all." - Cunk on Britain S1 E1
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darkone
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Re: ham international jumbo not transmitting after few minut

Post by darkone »

Otter wrote:
darkone wrote: or AVR pass transistor failing.
Or a "plated through hole" near the transistor going open circuit as the transistor heats up. I've seen that.
Yup. Entirely possible.
"Far from idleness being the root of all evil, it is rather the only true good."
Soren Kierkegaard - Danish philosopher (1813 - 1855)
cubwolf
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Re: ham international jumbo not transmitting after few minut

Post by cubwolf »

I am assuming this is the Mk1 with the 059 board in?
The plated through the pcb hole thing is a 121/125 issue
Before you change the PLL or VCO its worth checking that you still have 10.240 on TP1.
This would be your first point to check as its the reference for the pll chip.
If thats not there it wont work.
I am seeing more and more cases like this in Jumbos and Multimode 2s etc where C11 (560pf) is going short circuit after a few minutes of use.
Its on the base of Q3 the 10.240 oscillator
Its a mica style capacitor and for some reason in the last 2 -3 years more and more have started failing.
Thats only a few pence and is always worth checking before you start changing the pll and vco
davie_1977
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Re: ham international jumbo not transmitting after few minut

Post by davie_1977 »

thanks for all the replies you have all been helpfull but sorry dont know a thing about it inside i mean i had a superstar 3900 multimode many many years ago i am a memeber of delta tangos 108 division scotland i was going to put it on ebay for spares or repair but by the looks of things it cheap to sort but dont know were to start
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163TM847
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Re: ham international jumbo not transmitting after few minut

Post by 163TM847 »

cubwolf wrote: I am seeing more and more cases like this in Jumbos and Multimode 2s etc where C11 (560pf) is going short circuit after a few minutes of use.
Its on the base of Q3 the 10.240 oscillator
Its a mica style capacitor and for some reason in the last 2 -3 years more and more have started failing.
Thats only a few pence and is always worth checking before you start changing the pll and vco
Yes i remember an MM2 i had having that fault once about 2yrs ago, An easy way of identifying that fault i noticed is the FM Receive audio goes alot quieter than a VCO or PLL failure.
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Re: ham international jumbo not transmitting after few minut

Post by cubwolf »

Indeed it does :-)
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Otter
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Re: ham international jumbo not transmitting after few minut

Post by Otter »

cubwolf wrote: The plated through the pcb hole thing is a 121/125 issue
And PCMA001S, I've seen it on that board too. I must admit I haven't seen it on 059, but I do as little as possible with 059. I really don't like them.
I wouldn't knowingly buy a radio with the 059 board in it unless it came in a job lot with something I wanted.
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Re: ham international jumbo not transmitting after few minut

Post by cubwolf »

yes your right. But the 001 is only a 125 with slight mods and green paint.
I am with you on the 059 chassis. Its not one of my favourites either
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163TM847
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Re: ham international jumbo not transmitting after few minut

Post by 163TM847 »

The last 2 comments has too be honest really surprised me, Over the years i have always found the 059 to be the better of the cybernet range, Granted the FM TX audio (unmodded) has let it down but the SSB TX audio & output has always been the better out of the others.

Is it just me who thinks this, Am i on my own here :D
Last edited by 163TM847 on 13 Apr 2010, 22:52, edited 1 time in total.
cubwolf
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Re: ham international jumbo not transmitting after few minut

Post by cubwolf »

I was mostly talking from a modding point of view etc.
The ssb on the 059 is better than most of the others i will grant you that.

Personally my 3 series radios (Concorde 3 and Jumbo 3) were the ones i found the best all rounders but again only after modding them.
Shame they are so rare. Wish i had kept me Jumbo .

Slightly modded lol
Image

Meanwhile back on topic.
Have you fixed the Jumbo yet?
Last edited by cubwolf on 13 Apr 2010, 22:42, edited 1 time in total.
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darkone
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Re: ham international jumbo not transmitting after few minut

Post by darkone »

Black Spirit wrote:Is it just me who thinks this, Am i on my own here :D
I've said before that the 059 board is my fave cybernet.
Good SSB and adjustable VCO voltage.
048 is a close second for me.
"Far from idleness being the root of all evil, it is rather the only true good."
Soren Kierkegaard - Danish philosopher (1813 - 1855)
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