|Board Swapping ie.. I do it all the time when FT301 trouble shooting.
but..now I am taking a more careful approach!!
|This is just being written 21- Nov 2014. I am being more careful now when doing board swaps from a defective radio (ie FT301) to a good radio.
Above pictured .. a bunch of the RF BOARDS from the FT301 I am currently working on. -- To the right..part of a circuit board finger conductor
came loose and I (think) it shorted something out in one of my radios.
These are the kinds of things to look for when doing a VISUAL INSPECTION before doing the electronic troubleshooting itself !
What I do NOW..is I do a good visual examination of the defective circuit board..carefully comparing it with the good circuit board. I look for
problems such as bad connections or solder joints. BEFORE ..plugging it in to the good working radio.. I also now do a careful resistance check
of all the major plug in connections. 18 for these FT301 boards. I compare the good board readings with the bad board readings. This is to
ensure I dont short something out on a good working FT301. Sometimes..with these resistance checks..you can find faults right off the bat as
well. -- JUST THOUGHT ID PASS THIS ON AS AN IMPORTANT STEP IN PROBLEM SOLVING FOR THOSE OF YOU WHO STILL WORK AT TROUBLE
SHOOTING OLD RIGS (or even newer stuff as well).
With old rigs like FT301s and other Yaesu Rigs and some Heathkits.. sometimes a person will have 2 radios ..one as a back up and/or parts rig to
draw parts from and another for an operating radio.
I have an FT221R that works great! Nice radio and I really like it..though up here in Northern Ontario there is not much ssb activity. I use it on FM.
I also have an FT221R that doesnt work. Bought it inexpensively from a fellow in town. By doing the board swapping thing.. I found the defective
board in short order. It was the PLL board.
|this article is just being written today.. 21
NOV 2014 .. and will be finished soon.
73 Earl VE3AB
|Heathkit NOTE regarding Board Swapping and FT301 and Other radios. -- Lets take a page out of one of the Heathkit
manuals. -- When you build a Heathkit Kit (or when you used to build a Heathkit Kit).. the last step in the main construction
process (prior to putting power to any of the circuitry) was to do a resistance check on the kit. You would check about 5
or 6 key locations in the circuitry you just built and do resistance checks to ensure that when you apply power to the kit
..you would not see smoke !! --- SAME GOES FOR BOARD SWAPPING. If you have time..do some resistance checks and you
are less likely to cause problems.
|Article by Earl Andrews VE3AB
November 23 2014
www.earlandrews.com (mirror sites)
Paid for by VE3AB through sales of components and
the odd repair I do - no advertising on line magazine.
|LOOKY HERE -->>
|Mr Andrews (VE3AB),
For a while now, I have had a Yaesu FT-221 which has an interesting issue which I have failed to isolate; TX fails to ping a repeater, but works on simplex/no offset.
After transmit, though, (in any mode), the RX (also in any mode) fails. As well as this, the RX fails after changing the "Band" switch, "Channel" switch, or switching the
"NOR" repeater offset reverser. It will, however, pick up a transmission from my nearby HT. In short, it seems to fail whenever there is a switch in frequency involving a
change in physical contact (VFO can still tune in/out a signal), or at least weaken reception to unusable levels. The RX problem goes away after switching the radio
off, then on again. What I believe so far is that the issue is not related to the separate IF sections, audio, or relays, since the radio receives after using the marker and
FM discriminator. It may be capacitance related. Could this be the final? What should I do to diagnose/resolve the issue? I have read your article on the "black series,"
and my specimen's issue remains unique. Thanks for your consideration,
|Ok Erik. Thanks for writing. Interesting situation you have there. I wonder if it could be the Phase Lock Loop board? I have an FT221R here with a bad PLL board that
I haven't gotten around to fixing yet. Someone wrote me that he cured the PLL board by cleaning one of the potentiometers on the PLL. I think that's what he said.
Was a while ago. I have 2 FT221s here. One works and one still needs that repair done. I did some board swapping between the
2 radios to narrow the fault down to the PLL board. - IF you could buy a working FT221 and try that..that might be an idea.
I would also try and eliminate the power supply - power source as a problem. I haven't tried it with my FT221R but I (think) there is a provision
to power it on DC rather than with the internal power supply. That might be an idea to try.
Could be a bad electrolytic cap that causing the DC power line to be a bit flaky.
Just some ideas .. I might think of a few more and I can write you back. 73 and good luck with the radio. It is an old favorite of mine here. Earl VE3AB
I toyed with the PLL circuit until I found a solder glob on the bottom of the board, and removed it. I also re-tuned the pot in the front of the board and low and
behold---it works! It has no issues, pings repeaters, RX works fine now and lights will flash if unlocked (having removed that solder glob!) Thank you very much
for the advice! I read into what the PLL is for from the service manual, and I was shocked to see it was part of the oscillator system. This being my first solid state
base station rig, it totally slipped my mind, derp. Thanks again, and I hope you can get your other 221 working!
|ALSO.. an FT221R repair ..my advice worked this time !!!!!!