Has anyone seen or worked on a CHAPMAN S6BS? I was asked to re install the tubes on this unit after someone has removed them, I can't find any schematics so I'm stuck.
I searched and found this: EF41 RF amplifier ECH42 Frequency changer EF41 1st IF EF41 2nd IF EBF80 AGC IF, AGC rectifier, Demodulator And that would be the Mark I version. There was also 3 x EF89, ECH81, EBF80. It's English, so maybe a English member would be able to find more. Might have to ask at DIYAudio.
Chapman S6BS/FM Valves: three EF89, ECH81, EM84, EF85, ECF80, two EF80, EB91, EZ80, EBF80. Frequency range: 37-108 Mc/s, 11m, 13m, 16m, 19m, 25m, and 31m in six band spread ranges, 13-43m, 43-140m, 175-570m. Power supply: 110V and 200/250V 50 c/s. Consumption: 65 watts.
The classic part is that all the info we are getting seems to be wrong, there are only 7 tubes. GZ80, EBF80, ECH81, EM84, EF89. EF89, and the last one has the markings rubbed off but it looks like a EF89. here are some pics.
It should be kinda easy to find out where most of them go. The ECH81 is a oscillator/convertor, it should go near the capacitor gang, in one of those two sockets. Since pin8 is the anode for the heptode section, it should goto a transformer in one of the cans. Also since the ECH81 has two anodes, both should have voltage on them if powered up; pins 8 and 6. The EF89 will also have voltage on pins 7 and 8, where pin 7 will go into a transformer can, and pin 8 will have a small film capacitor on it for filtering. Pins 1 and/or 6 will be grounded. The EBF80 will be at the end of the IF chain because the diodes are needed for detector/descriminator. It should go to the socket all the way to the left. Pins 6, 7, and 8 should all go into that can beside it. The GZ80 should be a EZ80, it should goto the bottom socket on the left. Make sure you have 2 smaller wires coming from the transformer to pins 1 and 7. Pin 3 should goto a electrolytic filter capacitor.