I have succesfully done this mod and it works great!!
The radio was actually designed for 3 bands and one of the bands was 134-150mhz (model a). I tried to retune the coils for receiveing on 2 meter but they just would not make it. Fortunately, the schematics show what parts differ from each version made! Basically I had to INCREASE the value of certain capacitors in the circuit to turn the unit into a model A. The great part about that is that capacitors in parallel add so I was able to just turn the unit over and just solder 1pf to 5pf capacitors where needed on the back of the circuit board in parallel with the current caps without having to desolder a single component. That made it very easy!! Once that was done, I followed the service manual's instructions for retuning the unit up completely from receiver to xmiter. I can get a full 40 watts out if I push it but I set it down to 25 because I wanted to have longer qso's without heating up the finals too much. If you want a photo of the back of my unit to show you where the caps I added went I can possibly do that as well. Here is a list of the capacitors I modified by soldering ceramic
disc caps on the back of the circuit board in parallel. You don't need to match exactly just get close and
you'll be ok.C208 from 6.8pf to 22pf
c210 from 8.2pf to 22pf
c303 from 82pf to 150pf
c414 from 6.8pf to 8.2pf
c416 from 8.2pf to 10pf
c419 from 5.6pf to 6.8pf
c421 from 8.2pf to 10pf
c426 from 6.8pf to 8.2pf
c428 from 6.8pf to 8.2pf
c526 from 3.3pf to 4.7pf
c528 from 6.8pf to 10pf
c529 from 3.8pf to 4.7pf
c534 from 6.8pf to 10pf
c537 from 22pf to 27pf
Once completed then tune per the service manual located here:http://www.repeater-builder.com/relm-regency-wilson/pdfs/rh250-rh256-wh516-svc-manual.pdf
A WORD OF CAUTION: You may have to remove the front control head during tuning of the coils underneath. Try not to disconnect the thin membrane keypad connector. The others are hard wire
and they are fine but the thin membrane connector may get scraped or damaged by removing it
especially if it is old and it will not conduct properly anymore rendering the keypad useless. Trust
me I know!
Hope this helps, it's a great unit. Next step for me is to figure out how data is clocked into the pll synthesizer chips and I'm going to make a new front end for the unit with a vfd display, tuning knob and other features I wanted rather than just the 10 selected freqs. BTW, the manual explains how to program the frequencies and you will need to program at least 3 144mhz 146mhz (center band) and 148mhz for proper tuning and alignment.