Thanks Al. Yeah, I thought of that. At the risk of
overthinking this:
- no ALC light at all
- zero output (both finals gone?)
- zero additional current (finals are not shorted?)
- both open? maybe the bias circuit is gone? shorted but
took out the meter shunt?
Anyway, I am going to gently separate the PA module and take
some measurements and
see where we are before I go out and buy a new pair (it
appears that RF Parts has the originals in stock)
Bill W1PA
-----Original Message-----
From: Al Gulseth
Sent: Monday, October 26, 2015 12:23 PM
To: tentec@contesting.com
Cc: Bill ACITO, W1PA
Subject: Re: [TenTec] Corsair I refurb project
Maybe not very likely, but perhaps check the 0.015 ohm
current shunt resistor
to make sure it's not open or that there's not a bad solder
joint on the
board? I.e. make sure there's power to the finals first
before going further.
73, Al
On Mon October 26 2015 9:54:09 am Bill ACITO, W1PA wrote:
Number 1 is fixed. As pointed out/suggested – loose
crystals. I should
have know this from my Omni-A/D/C experience.
>>No RX 160 and 80: freq counter bounces around on 0.180
>>to 0.190 Mhz on
>> these bands. I assume I should be looking at the wafer
>> switches and
>> oscillators? All other bands are fine on RX.
Now on to #2:
On transmit I see no power, and no current draw.
What’s the best way to diagnose the PA module? Voltage
checks on the
transistors themselves? Check the bias circuit? Should I
just replace all
four?
Has anyone successfully substituted for the MRF-458’s, and
if so, what did
you use? Do any other rigs use the same PA module (80565)
that I can swap
with? the 561 Corsair II?
>>No power out on TX -- zero. Scope says I have good
>>output from the
>>low-level driver board, which changes with the drive
>>control. Do the
>> finals fail open? Do they both go together?
>>Any easy way to check if it's the drivers or the actual
>>finals in the PA
>> module? I also read that there was a common T/R diode
>> fail that impacted
>> ALC? What were the symptoms of this fail?
Bill W1PA
_______________________________________________
TenTec mailing list
TenTec@contesting.com
http://lists.contesting.com/mailman/listinfo/tentec
_______________________________________________
TenTec mailing list
TenTec@contesting.com
http://lists.contesting.com/mailman/listinfo/tentec
|