Yaesu FT-100 repairs or The Perils of Buying Someone Else's Junk on eBay (Story time Part 2)

 After kicking myself a bit more, I started reading the FT-100 service manual and gathering up information about fixes, mods etc. and waited in hope that the seller would rip me off so I could claim a refund.

Unfortunately he honoured the sale and was deadly efficient at despatch.

Yay.

A few days later a parcel arrived, well packed, complete with original box, accessories and a reprinted copy of the user manual, the radio wasn't in bad shape cosmetically but, never a great sign, the screw heads were mangled from having been removed and reinserted a few times.

As a matter of course, whenever I buy second hand electronics from eBay I always check cables, fuses etc. and open the device up to make sure everything is as expected. 

Checking the cables, microphone, fuses etc. showed nothing untoward, so it was time to pull the cases off and take a look inside. 

Yikes.

Someone who no doubt styles themselves as a 'rig doctor' because they own a blowtorch and once worked out how to wrap cigarette carton foil round a blown fuse had bodged in the Yaesu factory SWR mods, soldered a couple of the Taiyo Yuden coax connectors into their sockets on the LPF board and generally made as good a job of the mods as an 800lb gorilla might have done.

There was also a fan mod using a resistor that wouldn't have been out of place in a 1950's valve radio and they'd burned a few of the connectors and cables from carelessness with their iron.

After kicking myself a few more times for good measure I took another look, it's definitely in need of TLC and a fair bit of tidying up but isn't too bad, the SRF7043 has a crack across the top which is pretty typical and explains the lack of TX power on VHF/UHF, everything else looks to be where it should be and all cables are securely fitted.

Once I was satisfied the radio wasn't about to let out the magic smoke I connected it to my lab PSU with the current limit wound down to roughly 1.5 Amps and success, it powers up but unfortunately it's as advertised, no output on VHF, UHF or HF.

It's also been widebanded and someone had been playing in the service menu as a few settings had been maxed out. 

To Be Continued




Comments

Post a Comment

Popular posts from this blog

Free GPS and a Merry Christmas

Image
 Season's greetings to one and all. I've been fascinated with GPS and GNSS in general for quite some time now, it feels rather miraculous that, for only a few pounds, I can buy a module not much larger than my thumb that will reliably provide my position anywhere on the planet to within a few metres by receiving signals from flying atomic clocks several thousand miles above my head. I've probably got far too many GPS receivers but recently someone posted an offer of free for the cost of postage receiver modules to the GQRP mailing list and it was too good an offer to turn down.  A few days later some nice little Leadtek modules arrived, complete with coax pigtails. As well as the modules, there was a zip file with pinout for the 1mm (?) pitch connector on the underside and a datasheet for the module itself. While they're quite old, they have a SiRFStar chipset which is a decent performer and I've always found them to be reliably fast to get and hold a fix.  Unfortun
Read more

MiniPA 70 build, almost there.

Image
A quick update, I needed a heatsink so I found one from an old PC which is more than adequate, weighing in at almost 650 grammes I reckon it should be able to handle the heat. Problem though, it's not flat. Which makes it kind of difficult to mount the board. Now, I could use some standoffs, PCB pillars cut to length but I'm a little light on machine tools to make an accurate job of it and it'd annoy me that it was 'wobbly'. As it happens, I recently bought myself a new toy. A Flashforge 3D printer so this seemed an ideal opportunity to learn to use a CAD program and find out how dimensionally accurate the printer is. It turns out, it's pretty good. And the PLA takes a thread really nicely. So, my Mini PA board now has mounts, I just need to drill and tap some holes in the heatsink.
Read more

Replacing the Teensy 3.2 with 4.0 in the GQRP SCD Sudden Digital VFO

Image
 Place holder for GQRP SCD Digital VFO Post   The chip shortage has struck down the Teensy 3.2 which was used in the GQRP Digital VFO here: https://www.gqrp.com/suddenvfo.htm   Obviously that's a problem.  However, there is light at the end of the tunnel, the Teensy 4.0 is pin compatible so could be a drop in replacement.   I downloaded the 'sketch' and tried to compile it, which failed with what looked like potentially simple to resolve errors and a *lot* of warnings about unused and uninitialised variables. The information below shows the changes I made to the V0_13 sketch and get a successful compile.   Compiled for Teensy 4 using Arduino IDE: Version: 2.1.0 Date: 2023-04-19T15:31:10.185Z CLI Version: 0.32.2 Errors with unmodified sketch when compiled for Teensy 4  "Sorry, i2c_t3 only works on Teensy LC and 3.x.  Use Wire for Teensy 4.0, 4.1, MicroMod." To fix: Change every instance of i2c_t3.h to wires.h In:  SCD_2021_V0__13.ino Si5351.h Si5351.cpp To mop up s
Read more