Dave, Stephen and Albert,
My unit is serial 90XX (forgot already), and as was noted, has a 6DJ8 for V70, although the chassis panel lists the 6BQ7 as well.
Not sure if I am going to the dungeon tonight, pretty beat after work today, but will take the pointers thus so graciously given and look at it tomorrow. When I prodded it with the 'scope probe, didn't get the voltages, so will check those along with the frequency and report back. Been given a lot of information and after a good nights rest, will put fresher eyeballs on it.
As for the calibration, I am fortunate to have snagged an S-30 Delta standard somewhere a few years ago. Have only given it a cursory inspection, but it appears to have never been tampered with. In fact, it looks almost new.
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On 2/17/22 14:45, Dave Wise wrote:
No big deal, I just wanted to ensure the archive doesn¡¯t mislead the next guy.
Once the OP has the multivibrator sorted out, there¡¯s a home-grown calibration technique that doesn¡¯t require the S-30 Delta Standard, just one precise capacitor and a frequency counter. (The latter wasn¡¯t commonly available when the 130 was created.) See ¡°/g/TekScopes/topic/tpe_130_l_c_meter_calibration/7656928¡±.
If you see nonlinearity on the 3, 10, or 30 ranges, look at C94, C93, and C92. Even if they are not leaky, the paper or paper-plastic caps Tek used are prone to Dielectric Absorption and this application is sensitive to it. But take care not to over-correct ¨C those caps weren¡¯t particularly good even new, and Tek printed the meter scales to match them. I installed polypropylene caps only to find that I was (slightly) off in the opposite direction! Use polyester instead.
Dave Wise
From: [email protected] <[email protected]> On Behalf Of SCMenasian via groups.io
Sent: Thursday, February 17, 2022 11:21 AM
To: [email protected]
Subject: Re: [TekScopes] Type 130 L-C Meter
You're right. Sorry for the confusion.
Stephen Menasian
