Old thread, but I'd like to reiterate how helpful Leader is with these manuals. I just requested a manual for a LAG-120B i purchased and they responded with a complete service manual .pdf in English within the hour.
Also, there is a pretty large difference between the 120A and 120B comparing the schematics. The square wave generator circuit is completely different, and the 120B uses a symmetrical power supply based on LM7824/LM7924 regulators vs. the discrete regulator found in the 120A.
Also, there is a pretty large difference between the 120A and 120B comparing the schematics. The square wave generator circuit is completely different, and the 120B uses a symmetrical power supply based on LM7824/LM7924 regulators vs. the discrete regulator found in the 120A.
LAG-120A malfunction
Hello everyone,
I have a LAG-120A which is giving me some trouble.
As I received it from a frined, it was producing a distorted waveform wich stayed always around 4-8 Hz no matter the settings of the front panel.
I could not find the 120A service manual, but the 120B service manual mentions that if the output signal is distorter, the TH101 Thermistor should be checked for continuity.
I did exactly that and I had to bend it slightly. As soon as I moved the TH101 my LAG-120A started to work. On the higher frequency settings the amplitude of the signal is not always stable....
I have tried to find a supplier or datasheet of the TH1 thermistor without any success. All it says on the schematic is " TH101 STT-300H"
Google is no help. The best I found is a chinese forum where someone asks the exact same question:
Where is it possible to get a STT-300H or a modern substitute. Or a least its specifications....
Thanks for reading and Best Regards,
Rafaekl
So my question is
Hello everyone,
I have a LAG-120A which is giving me some trouble.
As I received it from a frined, it was producing a distorted waveform wich stayed always around 4-8 Hz no matter the settings of the front panel.
I could not find the 120A service manual, but the 120B service manual mentions that if the output signal is distorter, the TH101 Thermistor should be checked for continuity.
I did exactly that and I had to bend it slightly. As soon as I moved the TH101 my LAG-120A started to work. On the higher frequency settings the amplitude of the signal is not always stable....
I have tried to find a supplier or datasheet of the TH1 thermistor without any success. All it says on the schematic is " TH101 STT-300H"
Google is no help. The best I found is a chinese forum where someone asks the exact same question:
Where is it possible to get a STT-300H or a modern substitute. Or a least its specifications....
Thanks for reading and Best Regards,
Rafaekl
So my question is
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