It all started when a friend told me about his cherry TRC-458, He'd has several tech's work on it and he wanted me to swap out all the electrolytic cap's.
He said it just DIDN'T seam rite, He though the audio CLIPPED out but it was his call to change the cap's. So i volunteered my services,
After seeing unit 399, J. J's article and doing the research on some cap kit's use cheap cap's. i decided to go through the sam's book and select the best and 105*C Nichicon cap's with atleast 25V there were in Mouser's website, I also grabbed extra's, some diodes, ect, I placed the order and swapped out the cap's, (What a PITA), Anyway. After all was said and done i performed the alignment according to Sam's and i wasn't happy at all with the SSB transmit and receive. I found a service manual that JJ posted and i followed it and i was happy.
After many day's of test driving the radio i returned it to the friend and i received payment.
A few week's passed and the friend said that USB was putting out more watt's and it seamed to drift in frequency after a good warm up. I always let my gear warm up and even cover it with a towel to keep it warm,
I got the radio back and after e-mailing JJ and several chat's he said to recheck his website because he updated some info. And low and behold there was a picture of the cap's to swap out and there were some Tant, cap's i wasn't aware of. Order more part's and replace the forgotten tant, cap's,
Fast forward past another realignment and to the testing. Now i run a Maco 750 and while testing the maco failed to key up, I tested the maco with my IC-718 and it wasn't keying with the icom either.
So off to the bench the maco goes for a recap and foot petal key up setup to bypass the RF keying system, Everything was good and the maco is working again with the Icom, I grab the TRC-458 and there is no power output from it. Back to the bench goes the TRC-458, The 1st thing i check is the driver and final bias amp draw, Well the Driver pegged my meter out and i pulled the driver and the final and test with my transistor tester and the driver was fubar. I alway's set the adjustment's rite on the money and i know the bias amperage was in speck.
I bought some 2SC1306's and 1307's from a seller on e-bay because Mouser didn't stock them and installed the part's and still nadda, Learning about fake transistor's and all was a hind site, After learning that the driver can be swapped with a 2SC2166 and the final with a 2SC1969, I ordered some HG 2SC2166's and some HG2SC1969's from ICA. I installed these part's, set the bias and ran through the alignment again and again no watt's output, I have double checked the bias amperage, Went back through the pll and transmit alignment so may time's my head hurt's.
Now i do have one advantage. I have a working TRC-458 here and i thought, I'll pull the driver and final out of the non working 458 and put them in the working 458, Low and behold the working 458 still work's. my plan was to swap the driver and final from the working 458 to the non working 458, but 2 leg's broke off the driver and i just put the hg's in the non working and it's still inop.
Now before anyone ask me what the dc voltages and all, I don't think the dc volt suggestion's in the sam's diagram are kosher, I can check the voltages between the working radio and the inop one and there both close to each other and not what the sam's diagram say's. The differences are in the C of the driver and the C of the final. Sam's say's 4.7VDC on the driver and 4.9VDC on TX for the final and The non working 458 show's 8VDC on both, the working 458 shows 11VDC on driver and 43VDC on the final. The negitive lead's are connected to board ground not chassis ground. I dunno why the working final c volt's is so high.
Now here's the kicker, On the working 458, On channel 1, 26.965mhZ i can hook up a freq counter and probe FET 6, G & D, TR45 C, TR44 C, TR43, C and the output at the coax and the freq counter read's 26.965 , Now when i probe G2 of FET7 i get 7.8mhZ and G1 i get 34.7mhZ, This goes through FET7 and 26.965mhZ merges from the output. The non working 458 is fubar from here,
The non working 458's input's into FET are the same, But it's the output that's different, The D of FET7 is the same as the input of G1 34.7mhZ.
I've swapped the FET7 from the working 458 to the non working 458 and the working one still work's, Ive done the same swap with FET6 and TR45.......
Since everything from FET7's output is fubar, I believe this is my low power problem. I can get around 1/2 watt out of the non working 458 and when i do, the output freq is around 21mhZ, To me it's like having a vfo on a browning and your trying to talk so far out of the 11 meter band, ya drop the output power.
BTW before ya say, Why am i getting 7/8 mhZ on G2 on FET7,,, It's becuse eather the sam's wiring code that shows' the 7.8mhZ going to G1 in the wiring diagram is wrong or the pin out on page 52 is wrong. I have a board here that i traced and the path from the 7.8mhZ, L39 goes to G2 of FET7 not G1 like the wiring diagram on page 78.
I messed with this non working 458 for a whole week, checking this and that, swapping part's and all so much i need a break, Time to recap another Tram d-201 until i get my head straight.
If anyone has any idea's and can explain all this, and help me fix it, I'll buy ya a steak dinner,
Later's Scott from Colorado
He said it just DIDN'T seam rite, He though the audio CLIPPED out but it was his call to change the cap's. So i volunteered my services,
After seeing unit 399, J. J's article and doing the research on some cap kit's use cheap cap's. i decided to go through the sam's book and select the best and 105*C Nichicon cap's with atleast 25V there were in Mouser's website, I also grabbed extra's, some diodes, ect, I placed the order and swapped out the cap's, (What a PITA), Anyway. After all was said and done i performed the alignment according to Sam's and i wasn't happy at all with the SSB transmit and receive. I found a service manual that JJ posted and i followed it and i was happy.
After many day's of test driving the radio i returned it to the friend and i received payment.
A few week's passed and the friend said that USB was putting out more watt's and it seamed to drift in frequency after a good warm up. I always let my gear warm up and even cover it with a towel to keep it warm,
I got the radio back and after e-mailing JJ and several chat's he said to recheck his website because he updated some info. And low and behold there was a picture of the cap's to swap out and there were some Tant, cap's i wasn't aware of. Order more part's and replace the forgotten tant, cap's,
Fast forward past another realignment and to the testing. Now i run a Maco 750 and while testing the maco failed to key up, I tested the maco with my IC-718 and it wasn't keying with the icom either.
So off to the bench the maco goes for a recap and foot petal key up setup to bypass the RF keying system, Everything was good and the maco is working again with the Icom, I grab the TRC-458 and there is no power output from it. Back to the bench goes the TRC-458, The 1st thing i check is the driver and final bias amp draw, Well the Driver pegged my meter out and i pulled the driver and the final and test with my transistor tester and the driver was fubar. I alway's set the adjustment's rite on the money and i know the bias amperage was in speck.
I bought some 2SC1306's and 1307's from a seller on e-bay because Mouser didn't stock them and installed the part's and still nadda, Learning about fake transistor's and all was a hind site, After learning that the driver can be swapped with a 2SC2166 and the final with a 2SC1969, I ordered some HG 2SC2166's and some HG2SC1969's from ICA. I installed these part's, set the bias and ran through the alignment again and again no watt's output, I have double checked the bias amperage, Went back through the pll and transmit alignment so may time's my head hurt's.
Now i do have one advantage. I have a working TRC-458 here and i thought, I'll pull the driver and final out of the non working 458 and put them in the working 458, Low and behold the working 458 still work's. my plan was to swap the driver and final from the working 458 to the non working 458, but 2 leg's broke off the driver and i just put the hg's in the non working and it's still inop.
Now before anyone ask me what the dc voltages and all, I don't think the dc volt suggestion's in the sam's diagram are kosher, I can check the voltages between the working radio and the inop one and there both close to each other and not what the sam's diagram say's. The differences are in the C of the driver and the C of the final. Sam's say's 4.7VDC on the driver and 4.9VDC on TX for the final and The non working 458 show's 8VDC on both, the working 458 shows 11VDC on driver and 43VDC on the final. The negitive lead's are connected to board ground not chassis ground. I dunno why the working final c volt's is so high.
Now here's the kicker, On the working 458, On channel 1, 26.965mhZ i can hook up a freq counter and probe FET 6, G & D, TR45 C, TR44 C, TR43, C and the output at the coax and the freq counter read's 26.965 , Now when i probe G2 of FET7 i get 7.8mhZ and G1 i get 34.7mhZ, This goes through FET7 and 26.965mhZ merges from the output. The non working 458 is fubar from here,
The non working 458's input's into FET are the same, But it's the output that's different, The D of FET7 is the same as the input of G1 34.7mhZ.
I've swapped the FET7 from the working 458 to the non working 458 and the working one still work's, Ive done the same swap with FET6 and TR45.......
Since everything from FET7's output is fubar, I believe this is my low power problem. I can get around 1/2 watt out of the non working 458 and when i do, the output freq is around 21mhZ, To me it's like having a vfo on a browning and your trying to talk so far out of the 11 meter band, ya drop the output power.
BTW before ya say, Why am i getting 7/8 mhZ on G2 on FET7,,, It's becuse eather the sam's wiring code that shows' the 7.8mhZ going to G1 in the wiring diagram is wrong or the pin out on page 52 is wrong. I have a board here that i traced and the path from the 7.8mhZ, L39 goes to G2 of FET7 not G1 like the wiring diagram on page 78.
I messed with this non working 458 for a whole week, checking this and that, swapping part's and all so much i need a break, Time to recap another Tram d-201 until i get my head straight.
If anyone has any idea's and can explain all this, and help me fix it, I'll buy ya a steak dinner,
Later's Scott from Colorado
