08-24-2014, 07:01 AM
Here is the Dynakit Stereo-70 that I acquired recently. I am in the process of bringing it back to life. I spent time cleaning the chassis and removing a Rotron fan that had been added to the right side of the top cover, tightened the contacts in the output tube sockets, replaced the selenium bias rectifier with a 1N4006 silicon rectifier. Inspection showed that one output transformer was bad. A new transformer is on order from Heyboer Transformer Co. I have a selection of new resistors on order from Antique Electronic Supply. I have some film type capacitors on hand already to replace those. Bfrohwein gave me some used 6CA7s to use for a test. I just finished making circuit trace cuts and jumper wire connections to convert the OEM board to use 6GH8 tubes yesterday. I did a recheck to make sure I got the connections right. The cathode, signal grid and plate are the connections of the pentode section of the driver/inverter stage that change connection. I intend to order a power supply board from Joe Curcio to replace the can electrolytic with individual electrolytics. The rectifier tube could be changed to silicon rectifiers, but for now I think I will keep the tube.
Joe
Joe