It seems to be a trend to use already designed & tested amp modules.
This one uses the UCD power supply and amplifier modules.
It appears the only EV item is the preamp.
Here is a file folder of info that I found on the UCD equipment. UCD.zip
The main amp uses two of the modules in push pull arrangment while the high freq's are covered by one solo module.
The fault condition that I encountered was the power supply would shut down after turn on.
One of the main amp modules had shorted output fets (ST p14nf12 fp).
If this is what you are encountering, you can pull all three modules to see if the power supply will stay on.
Plugging in one module at a time, while monitoring the PS, will reveal the bad module.
Edit: here is a pic of the amplifier assembly showing the UCD modules along the top of the frame.
In the primary part. connection of the cathode D43 to the anodes D15, D16 and R1.
Ref. D33 is D35, D23-26 (according to the schematic) SOD-323 in different versions of AP, L9, 8b. https://www.diodes.com/assets/Datasheets/ds30098.pdf BAT54WS
C34, C35 -220p; C40, C41, C68 -10n; C19, C20, C21, C30 -1u; C31 -270p;
C53 -220n, C43 -430p; R24 -10k, R94 -100k, R46 -108k, R48 -100, R95 (TNC) -70-80. T35 (b) through R75. connected with pin.4 TL494.
Anodes D35, D14 and R48 should be used. are connected with R37, C31 and T13 (b).
The connection going to the left of the upper terminal R37, excluded - common node only for the elements R37, C31, T13 (e), C20, R38, vysv.13,14 TL494.
The capacitor in the secondary circuit C27 is C65 - 2.2 uF
C60 - 1nF
What about the preamp schematic? I'm in truble with the + and - 15V regulator build with a zener and a tip31 tip32 but it seems to have some sort of current limiter so I have every time I turn on different voltages.
Does anyone have the Preamp schematic they could share with me. In my case, supply to LF33cv 3.3 volt regulators is 20v which is shutting down the regulators. Needs to be less than 18v.
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