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| Replacement for the PM9610 Prescaler for Philips PM6654 High precision Counter |
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| Fraser:
My 6654C needs its powers supply refurbishing due to capacitor ageing. It has been on my to-do list for ages so I am going to rehome it. This also means that I no longer need my Prescaler upgrade PCB's. After reading this thread I purchased two of the PCB's and some of the key components from the OP. I will sell the PCB's and parts for what I paid for them. PM me if interested. Update : Just checked on pricing...... I paid 30 Euros for 2 boards, 2 MMICs and 3 Prescaler-Chips. IIRC, at least one of the prescalers had been used by SaabFan for testing but carefully removed afterwards. Fraser UK |
| SaabFAN:
I've now updated the board to revision F. Changes: - Attenuator upgraded to handle up to 12 Vrms, as stated on the front panel of the instrument, and dissipate 5,9 dB of that power. - Prescaler-Footprints reconfigured with Jumpers, so different types of Prescalers can be used. - Removed the Notch-Filter for the Power-Detector. - Switched the connections of the OpAmp (Input is pulled BELOW 5V once RF-Power is applied). - Negative power-supply of the OpAmp is now regulated with a zener to -3,7V. (Suggestion by a User of the Circuit Maker-community) I'm thinking about using the unused board-space to add an AD8307 or a similar chip, capable of measuring RF-Power. An ADC or Microcontroller would then measure the output-voltage and make the digital information available by some means. USB-Connector at the rear or OLED-Display to be mounted externally would be possible. |
| FransW:
If you have front panel connections, the rear BNC ones are not used. Or the other way around. The Philips mini-coax connectors are a bit of a mystery. Either they are very obscure or a SMC type variant. Checking around this week. They seem to be used around the 80'ies / 90'ies. Educational: https://ewh.ieee.org/r1/new_york/tz/2007/20070315presentation.ppt and from the same site: Quartz Crystal Resonators and Oscillators Picture is from the same site. Regards, Frans |
| SaabFAN:
Yes, the connector on the coax-cable connected to the BNC-Connector in the front-panel is strange. But there's just enough coax-cable available for 2 attempts to solder an SMA-Connector to it. So I think using SMA-Connectors is the best way to go :) |
| FransW:
Also for the +5V test connector? |
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