Buying a SB-220? I'd worry first about parts that may be 25 to 35 years old. Most of what goes bad is available, but you could spend a bundle for the "100,000-mile tuneup". And if that's already been done, the sale price will reflect that investment. The seller will always want to get back the money spent for that kind of "upkeep".
Umm. If you have a SB-220 shipped, worry about damage in transit.
When it was sold as a kit, it arrived in three cartons. One with the tubes, another with JUST the big, heavy High Voltage transformer, and one more with all the other parts.
The later SB-221 version was sold "factory assembled". It also shipped in three cartons. Once you received them, you had to install the H.V. transformer. Four screws/nuts to hold it in, and one big plug that went into a matching socket on the chassis.
Heathkit warned in the manual NOT to ship one of these with that monster HV transformer bolted in place. If Heath had made the chassis heavy enough to take the stress, the price would have been a LOT higher.
We have seen a number of SB-220/221 amplifiers with the chassis deck warped by the stress of shipping, especially if the shipper is UPS. Had one that sheared the chassis deck completely away from the deck's rear flange where it bolts to the rear panel. Had to stitch it back together with right-angle brackets. Had to replace both circuit breakers, also.
If the deck warps downwards far enough, it will damage one or both of the circuit breakers. They are made from fairly brittle plastic.
There is no easy way to remove that HV transformer, especially if it's the "soldered-in" type.
Don't really have a useful, positive suggestion to offer, except to recommend "buyer beware" if you have one of these shipped to you. You sure don't want to plug one in after it arrives, unless you have removed the cover and looked for shipping damage. It really was not designed to ship, once assembled.
73
