Spectra UHF 45W A7 to A4 conversion

[VA3XDJ]

Hi!

I recently purchased a Spectra D44KMA7JA7BK radio which has an A7 head with defective VFD it seems. (3rd character and several top indicators not functioning properly.)

I have a working A4 head I'd like to use instead but RSS wont let me change it from Standard to Rotary.

Some have suggested a cloned codeplug or Spectra LAB?

The A7 head has been re-capped and the traces from IC to VFD between the caps look ok.

Would swapping VFDs work?

Thanks in advance for all your help.

I've worked with Radius mostly so the realm of Spectras is a new world for me.

Mike

[kcbooboo]

You can probably find another A2/A5/A7 head on fleabay and just swap the entire board, after recapping that as well.

VFDs usually die because the internal filament (heater) gets weak or burns out. Individual segments or digits not working is usually due to open foils on the circuit board. You can swap the actual VFD from another A2/A5/A7 head but I'm not sure if the A4 uses the same VFD as the other heads.

Bob M.

[jackhackett]

You might want to try resoldering the pins on the display, I've seen a lot of them that had corroded solder joints. Liquid spills or capacitor leakage seems to settle on those pins since they're at the bottom of the board.

Also leakage from the old caps can remain on the circuit board and cause problems with the display if the board wasn't cleaned well when the caps were replaced.

Like Bob said, individual digits out would probably be a connection problem. You could look at a schematic and see which pins and traces go to the affected segments and take a closer look at those.

[Jim202]

Hi!

I recently purchased a Spectra D44KMA7JA7BK radio which has an A7 head with defective VFD it seems. (3rd character and several top indicators not functioning properly.)

I have a working A4 head I'd like to use instead but RSS wont let me change it from Standard to Rotary.

Some have suggested a cloned codeplug or Spectra LAB?

The A7 head has been re-capped and the traces from IC to VFD between the caps look ok.

Would swapping VFDs work?

Thanks in advance for all your help.

I've worked with Radius mostly so the realm of Spectras is a new world for me.

Mike

You can use the software that has the MOFLAGS and go in the codeplug to change some of the settings. The other thing you could do is change some of the memory locations. It is a very helpful version of the software to let you change many of the features in the radio and control head settings. There are a few web pages with some information and what the different areas allow you to do. Try doing a search.

It's been a while since I have had to make those changes. I would have to look around my computers to locate the files with this information to point you to the correct places.

Jim

[VA3XDJ]

Thanks for all your help, guys!

I'm not very agile and lack dexterity with a soldering iron so I'll have it looked at by a friend who's more experienced with soldering jobs.

I hear messing with the MOFLAGS in Spectra LAB can be quite tricky so I'll wait and see what the inspection yields first.

[N4KVE]

Hi!

I recently purchased a Spectra D44KMA7JA7BK radio which has an A7 head with defective VFD it seems. (3rd character and several top indicators not functioning properly.)

This specifically is a sign the caps have leaked, & ruined the trace for the 3rd character. Either fix the trace, or get another A7 head. They are VERY cheap on that auction site. GARY