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Re: Grant PC-409AC (made 1980) help please
Posted: 09 Apr 2019, 10:47
by cb4ever104
dt307 wrote: ↑09 Apr 2019, 10:44
.....so if its good enough for them lol
Re: Grant PC-409AC (made 1980) help please
Posted: 09 Apr 2019, 10:49
by dt307
GT390 wrote: ↑08 Apr 2019, 20:51
I got some 945`s with the correct pin out and 733`s and replaced all TR21 to TR27 and saw some improvement and much less "white noise" on transmit but audio was still low and slightly distorted, I replaced the 458 (TR43) beside the audio chip with a 945 and swapped out C46 from a parts rig (links TR43 to TR21), swapping C46 made an improvement on the audio level to a receiver but it is still slightly distorted, I aligned the PLL section and TX this made another slight improvement but receive now is off frequency a bit ?? I will align that once I get my AF genny sorted.
So I still have the problem albeit much better than it was, I think I will replace the other green caps in the audio path as changing C46 did make a fair difference, what type of caps are they ? green dipped rectangle shaped are they poly, ceramic or tants ?
the green caps Polyester Capacitor polly film
Re: Grant PC-409AC (made 1980) help please
Posted: 09 Apr 2019, 20:30
by Otter
GT390 wrote: ↑08 Apr 2019, 20:51
I think I will replace the other green caps in the audio path as changing C46 did make a fair difference, what type of caps are they ? green dipped rectangle shaped are they poly, ceramic or tants ?
They're polypropylene caps, but I have never heard of one going wrong. Ever. Since 1980. Not a single one.
Re: Grant PC-409AC (made 1980) help please
Posted: 10 Apr 2019, 13:03
by GT390
Otter wrote: ↑09 Apr 2019, 20:30
GT390 wrote: ↑08 Apr 2019, 20:51
I think I will replace the other green caps in the audio path as changing C46 did make a fair difference, what type of caps are they ? green dipped rectangle shaped are they poly, ceramic or tants ?
They're polypropylene caps, but I have never heard of one going wrong. Ever. Since 1980. Not a single one.
I thought too that they were pretty bulletproof and the one I replaced c46 tests OK as far as I can test it. It's got me wondering now why it made a fair difference changing it. I have ordered up some new poly films anyway.
Re: Grant PC-409AC (made 1980) help please
Posted: 27 Apr 2019, 16:48
by GT390
dt307 wrote: ↑06 Apr 2019, 11:12
sorry been mental here with new grandson some 711 in the post bro
Chris can you PM your paypal email and I will send you a thank-you
Thank-you to all who helped get to the bottom of this, the fault was electrolytic C191 right at the band selector switch....installed wrong polarity..duh
All working fine now, thinking back I must have only made contacts on FM after installing the new caps and FM is on a separate board on this early set
thanks again
Robert
Re: Grant PC-409AC (made 1980) help please
Posted: 20 May 2023, 03:00
by Lwc407
help my -pc-409ac has had xtra chans 26mhz plus 5kc shift and 27mhz has bean added but the clarifier shists all the time how do i lock it to 12 o clock and wind the power down to 4 wts so it can have a 100wts amp on it. and i want to add fm to it as well.
pls any help would be good
73's lwc407 nz
Re: Grant PC-409AC (made 1980) help please
Posted: 28 May 2023, 07:08
by Tech2
Best advice would be to send it to Nick, Black Spirit.
You can contact him via the forum.
Re: Grant PC-409AC (made 1980) help please
Posted: 03 Jun 2023, 20:48
by cb4ever104
Tech2 wrote: ↑28 May 2023, 07:08
Best advice would be to send it to Nick, Black Spirit.
You can contact him via the forum.
The guy's callsign is "nz" , so I figure he's in New Zealand . If he is then Nick might not be his best option .