My manual scan covers serial numbers from the beginning to at least 10760. During that time, the 130 used a 6BH6 for V110, Guard Voltage Cathode Follower. It was always a 6BH6 and nothing else was ever a 6BH6. The V70 Multivibrator has always been a 6U8. The V76 Clamp Tube is ¡°Use 6DJ8¡± so early instruments were probably 6BQ7, an older dual triode that Tek globally replaced with 6DJ8 because the latter is more reliable.
If the multivibrator is not switching, then the input may not be swinging past one of the threshold voltages, upper or lower. What¡¯s the frequency and amplitude of the AC part of the input waveform? What are the DC voltages?
Dave Wise
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Sent: Thursday, February 17, 2022 5:12 AM
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[email protected]Subject: Re: [TekScopes] Type 130 L-C Meter
Jerome,
Are you sure the clamp tube should be a 6DJ8? I have a 130 (which I have converted to solid state) and the clamp tube is a 6BH6. Of course the 130 went through several iterations and your version may very well have a 6DJ8. The schematic I have shows a 6BH6 and the writing on the chassis near the tube socket says 6BH6. Mine worked well (until the main electrolytic capacitor in the power supply gave up the ghost); so, I'm fairly sure my tube is good. I am in Pennsylvania and can ship it to you for a nominal price, at your suggestion, including shipping.
Stephen Menasian
