Just got this 2220 in here a few days ago for a basic restore for a fellow. Just covering the phono/PS tone and amplifier boards and main caps, switch etc… Right next to the 2220B and 1060, the 2220 has got to be one of the easiest units to work on, the chassis is very open and accessible. The 2220 is an interesting unit, a pretty common PS noted on several of the lower watt 22XX units with no regulator adjustment. Also these models don't have the bi-pin functions. About the only qualm I have with this unit is its not properly shielding inside, otherwise their really great sounding lower watt receivers, with really clean simple plates.
All the caps were replaced with low ESR/high tempt Panasonic FR's which seem to be perfect for the PS. Three S1B-01-02 diodes at H804/805/808 were replaced with a single UF4005 diode. I've still got to scrape off some excess dried glue from the original caps along with some oozed flux on some PCB's, back then everything was so bulky, I thought about a larger diameter cap but I wasn't happy with specs VS size aesthetics in this case.
The tone board topography is very similar to the 2230 I noticed, I decided to keep the films present, the fat browns are hard to beat. Elna Silmic II's were used throughout and WIMA MKS2 were placed in the bi-polar section 701/702. This boards has a bunch 458's that the ksc1845's are a go to for. If one removes the tone control PCB the tone board pulls out completely almost and can be contorted easily for more access.
The axial here was replaced with the Nichicon TVX I like to use along with Elna Silmic II's and a KG. No diodes to update on this board but H905/906 845's were replaced with matched KSC1845's. The films again were the fat browns. I suppose if I were to replace them the only vie found to come close is the ECW PP panasonic films. Ive used them to replace the yuck original gray films.
I've never really been a fan of the symmetrical single PCB design when it comes to the amplifier board but alas. Access is fairly easy to pull the board from the unit with a few common grounds to mind. The other trick to this unit was the transistors. This model did not use transistor sockets for the TO-3 type, they used insulated hardware and soldered the leads…Talk about a PITA, if I come across a 2220 again it will most definitely be ordering sockets for it, if they can fit.
The bypass or 701/702 were replaced with small MKS2 .47ufs and Elna Silmic II's used throughout the amplifier board. New Mica and compound and well.
One thing I did like is the filter/coupling selection, I hate the amp boards smack next to these caps because of the radiant heat put off by the boards. So I kept my normal selection of a Panasonic THA (I think IMHO this is the best cap for this location, sonically better than the KG Ive tried) at the filter and Nichicon KG's but went with 35mm/35mm caps to create a low profile to try and open up some air volume between the caps and board. Im incredibly happy with how this turned out with the symmetric PCB layout
I did find a 10amp heavy duty automotive power switch inside originally that was replaced with a EG1018-ND dpdt switch and a new TDK X1Y2 safety cap. Threw in some new vellum and LED few lamps for the dial and meter. I did have to reflow the Stereo indicator, Ive had to do this is about a half dozen 22XX's now, either when folks either replace them or heat related solder wear im not sure.