I have a ft900 with the VCO4 issues (12M and up blinks). Reads 8v at the TP1003, versus 6v. I sprayed freeze spray on some of the surrounding electrolytics to see if i could aggravate it. For giggles I sprayed in the the adjustment hole for this VCO, TC1005, and the VCO sprang back to life, no blink. Could the variable cap get dirty and short?
Hello!. I am also working on an identical PLL-wise FT-890. In this case, the VCO-1 is at fault (so 0.1-7.499MHz fails). It works for some hours, then stop working for some minutes, then it is back working. I have already resoldered all the VCO-1 components, replaced the 2SK210, fullly realigned PLL... But it keeps failing. A nightmare, really, as accessing the bottom side of that circuit is awful. I have ordered some replacement varactor diodes and that will be the very last attempt to fix this
Yes, a bear to access the board(s) but it can be done. PLL out of lock problem turned out to be shorted 100uF cap on the 5v line right at the PLL chip itself. Definite bad caps issue, another same cap shorted on -9v line. OK now. Hope this helps someone out there.
I hate those coax TMP connectors. But when I have to extend or tap into something I bit the bullet and put together some TMP to BNC jumpers and TMP to TMP jumpers. There are a couple of places that sell male and female connectors to roll your own...but I still hate them!!! ;-)
I can't recall where I got them but the bookmarks I have lead me to believe the RF Connection may still have some, along with HD Communications Corp. and the last lead I had was Spectrum Component Sales where the page says that Taiko Denki connectors are "end of life" and they may have a limited supply; they listed a email address to contact. If you need the direct links send me a note via my ARRL address (KL0S; listed on QRZ). Did I mention that I hate those things? ;-)
working on the same problem now. if you still have your 900 I will keep you posted on my fix. mine was all apart, tnx for the pictures it help me. slow here so I say 1 to 2 months . hope to get it fixed keep you posted on it 73`s for now.
in a forum it someone with several 900s said it can be the 2SK210 fets in each of the four VCOs. but also said the inductors L1008 1016 1026 1032 loosen at the solder connection, steel pins I haven't had luck (no guts) pulling the local board out of the radio
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I have a ft900 with the VCO4 issues (12M and up blinks). Reads 8v at the TP1003, versus 6v. I sprayed freeze spray on some of the surrounding electrolytics to see if i could aggravate it. For giggles I sprayed in the the adjustment hole for this VCO, TC1005, and the VCO sprang back to life, no blink. Could the variable cap get dirty and short?
Hello!. I am also working on an identical PLL-wise FT-890. In this case, the VCO-1 is at fault (so 0.1-7.499MHz fails). It works for some hours, then stop working for some minutes, then it is back working. I have already resoldered all the VCO-1 components, replaced the 2SK210, fullly realigned PLL... But it keeps failing. A nightmare, really, as accessing the bottom side of that circuit is awful. I have ordered some replacement varactor diodes and that will be the very last attempt to fix this
Thank you for the video! VCO4 seem to be the issue with all the radios I have read about but did not see a fix.Did you ever track down the fault?
no, and sold the radio
Yes, a bear to access the board(s) but it can be done. PLL out of lock problem turned out to be shorted 100uF cap on the 5v line right at the PLL chip itself. Definite bad caps issue, another same cap shorted on -9v line. OK now. Hope this helps someone out there.
Know it been awhile. What board and the chip number the schematic I have is hard to read any part numbers. Thanks!
By the way, congrats on reaching video #250!
My FT 900 has the same problem. How many of us are suffering from this has anyone found a way to fix it
I hate those coax TMP connectors. But when I have to extend or tap into something I bit the bullet and put together some TMP to BNC jumpers and TMP to TMP jumpers. There are a couple of places that sell male and female connectors to roll your own...but I still hate them!!! ;-)
where did you get the TMP connectors. donor radio? it seems the TMP connectors are hard to find and expensive
I can't recall where I got them but the bookmarks I have lead me to believe the RF Connection may still have some, along with HD Communications Corp. and the last lead I had was Spectrum Component Sales where the page says that Taiko Denki connectors are "end of life" and they may have a limited supply; they listed a email address to contact. If you need the direct links send me a note via my ARRL address (KL0S; listed on QRZ). Did I mention that I hate those things? ;-)
I always have a hard time putting them back in!!!
So, you didn't got any improvement on that?
no, I sold it
working on the same problem now. if you still have your 900 I will keep you posted on my fix. mine was all apart, tnx for the pictures it help me. slow here so I say 1 to 2 months . hope to get it fixed keep you posted on it 73`s for now.
in a forum it someone with several 900s said it can be the 2SK210 fets in each of the four VCOs. but also said the inductors L1008 1016 1026 1032 loosen at the solder connection, steel pins
I haven't had luck (no guts) pulling the local board out of the radio
yes, tnx for the info. solder and that white stuff a clean up job at least
I have the same issue with mine to, I check voltage and it is spot on but on vfo 4 voltage is at 8.2v and wont come down..