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Adding counter to trc-457

jrd426

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Sep 5, 2018
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Hi guys, i picked up a counter a while back from a member which was originally sold many years ago i believe on freebay. I did get a paper that came with it but only covers removing the original clock and where to get the 12v source for its power.
So i went ahead and installed it where the clock was and did the connections for the power. I asked a friend where to connect the small coax wire which comes off a 4 pin connector (2 wires for power and the coax wire sh & center conductor) and he told me that the center conductor from the coax connects to TP-8 and the shield to the top of a near by can. This doesnt seem to work. The counter has power but when the radio is on it reads 61.236. I will try and add some pics of both the counter i have (trc457 silkscreened on the circuit board)..I am thinking i must not be connecting the small coax to the correct points on the 457 board. I dont see anywhere on the counter to mess with offsets etc. Any ideas or help would be appreciated.
 

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That's Ralph's 'Backwoods RF' counter, looks like. That one was meant to connect to the 858 chip's input on pin 11, or from the collector of TR31 that feeds into pin 11.

He had problems with the offset number stored in the PIC chip getting corrupted. Had something to do with the board's reset circuit. Never did dig any deeper than that. The two customers who had trouble with his display sent them back and he replaced them with 'patched' versions.

Haven't heard from Ralph in years. Did the instructions say to use TP8? If so, this is a totally different counter.

If I'm right, you find that hooking up to TR31 collector won't show any change in the reading when you turn the clarifier. This was Ralphs "end run" around the way this radio's VCO frequency jumps around when you transmit in AM mode, or change to sideband. Try it and see if I'm right.

73
 
That's Ralph's 'Backwoods RF' counter, looks like. That one was meant to connect to the 858 chip's input on pin 11, or from the collector of TR31 that feeds into pin 11.

He had problems with the offset number stored in the PIC chip getting corrupted. Had something to do with the board's reset circuit. Never did dig any deeper than that. The two customers who had trouble with his display sent them back and he replaced them with 'patched' versions.

Haven't heard from Ralph in years. Did the instructions say to use TP8? If so, this is a totally different counter.

If I'm right, you find that hooking up to TR31 collector won't show any change in the reading when you turn the clarifier. This was Ralphs "end run" around the way this radio's VCO frequency jumps around when you transmit in AM mode, or change to sideband. Try it and see if I'm right.

73
Hi Nomad, i didnt get any instructions with the counter, just a sheet that walked through removing the clock and connecting the counter for power. I guess there was a page 2 that didnt come. As for the connecting to tp8, that was just a suggestion a friend gave me to try which was a no go.
 
"connects to the 858 chip's VCO input on pin 11."
Is this connection to pin 11 made on the UHIC005 that underneath is covered with a metal shield by chance ? Sorry for the newb question on this. Me not being a tech figured i would be able to get this counter installed and working. :) 20250204_094603.jpg
 
At one end of the uPD858 PLL chip is a dimple in the edge. With this end of the chip facing upwards, pin number one is the corner pin on the left. The pins are numbered counterclockwise from there. Pin 12 would be at the opposite end of the same side as pin1, and pin 11 is the next-to-last pin on the left side.

73
 
Thanks Nomad for the info. uPD858 PLL chip for this not the 10 pin UHIC005. Have a great day!
 
holy crap nomad. that's a great idea. i'll try it the next time i do a san jian counter on an 858 radio.
Boy did my idiot light come on brightly just now. The cheap 6-digit counters on fleabay would do this trick, tapping off pin 11 of the 858 chip, just by setting the counter's offset to 26.055.

Shoulda caught on to that years ago. Thanks for tickling the brain cells.

73
 

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