I finished my SHFA5 amplifier. It is for a DS100 or 160. This is an amp I will put up for sale. I have several more that will be done for the same reason. 50’s and 70’s amps for the most part. I usually do this kind of amp work in the evenings an hour here and there. It has a loud hum on the bench. I believe it is due to my set up. I use an old turntable with a magnetic cartridge as my input. The test record is now the second copy of “I Can Help” by Billy Swan. I never get tires of it which is a good thing since I’ve heard it several hundred times now. I got a SHFA3 in from Joe R. and while tesing it there was a loud hum as well. That amp has a weak Channel 1. I called Jeff to see if I could put the SHFA5 in his DS and test it. Removing his and replacing it with mine will take longer than the actual testing.All I need to do is verify if there is a hum or not. While there he is giving me a couple of mono redhead cartridges. I say give. I’ll swap out work for him for them. He has a C he is hot to get the mech working. I will then turn around and sell one to a fellow that Terry L. introduced me to. The guy’s cartdridge crumbled when Terry removed it to inspect. I need to trace down why I have such a bad hum on the SHFA amps. I tested the ground from the turntable to the amp and it is solid. I’ll visit him next week and check the amp.

I’ve been reconditioning a couple more wallbox boards to test. Speaking of which…I’ve been trying to find out what SCS device Seeburg uses on the audio control. My DEC manual does not have a parts list. I got on ebay and found a fellow in Canada who sold me a service manual and a parts catalog. I have never seen a parts catalog for the DEC wallboxes and am looking forward to getting it. Victory Glass for some reason does not have this manual. I think they are happy to coast on whatever manuals they recieved when they bought AMR, the original publishers of reproduction manuals. I buy/use Seeburg manuals or the ones made by AMR for their quality. I bought one off of ebay once, cheap. It was a copy of a copy and looked like crap. The schematics were unusable.

I also received six gray boxes from Don S here in Texas. He let me have them at a real good price. He is the go-to guy for CD jukebox player units. I met him through the Seeburg Jukebox Collectors page on Facebook. I’ll re-condition these to sell. I’m somewhat known as the go-to guy for black and gray boxes. I’m tickled to get the grays. They’re not as plentiful as the black boxes and hard to come by. I have about a dozen now. I took the cases apart and threw the plastics in a container of water to soak for a couple days. It makes getting the paper labels off a lot easier. One evening I’ll start inspecting the boards and getting the units ready to test.

The last couple days I’ve been working on a SHP3 amplifier. I recieved it for repair through the mail. The customer reported that the left channel didn’t work. It had massive damage. The amplifier is supposed to have a 3.2A fuse and really, a 2A is more than sufficient. This one had a 7.5A fuse.It was not blown and since it didn’t blow the amp just toasted all the transistors in the left channel. All of them. The drivers had the worst physical damage I have ever seen. What started this mess? The amp had all original capacitors. Let me climb on my soapbox….OK. Any Seeburg equipment with original capacitors is overdue to have them replaced. I mean the electrolytic capacitors. It’s over 40 years since Seeburg made anything. An amp may work but the electrolytic caps dry out and turn into resistors or just short out and cause a lot of damage. If the fuse doesn’t blow then real damage happens. Traces usually literally burn off the board and components burst into flame and this amp was no different.

I replaced all the transistors on the driver board for the left channel. All the electrolytic caps on both boards and chassis except for the filters. They are good. The left channel outputs were changed as well. While troubleshooting to see what all was bad I found that one of the right channel output transistors was bad. I replaced both of those so as to have a matched pair. The bias pots got thoroughly cleaned. Several of the “safety” resistors, the 100 ohm 1/2w’s in front of the drivers, were changed out. I replace those with 1w resistors to give less chance of burning up. They’ll blow but not burn. A trace on the back of the driver board was also repaired with a section of wire neatly inserted into the burned gap. After setting the bias I bench tested the amp and it worked well. I played it a while then transferred it to the STD4. Plenty of volume and excellent tone. I played one record, House Of The Rising Sun very loud. Who wouldn’t? The amp bias creeped up. After the record was over I let themech go to rest and kept an eye on the bias. It slowly came down as the amp cooled. It had gotten to 19ma on the left and 8ma on the right. I reset both to 5ma and played a few more records. The bias stayed rock steady. Mission accomplished.