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Hello @Relayer,
and again sorry for the long delay. I have good news: The monitor works!
I think this is cause for celebration! I sure will celebrate some. Thank you so much @Relayer; you made this possible!
I changed the chinese replacement of TS467 to a proper Philips transistor and it...
Hello again @Relayer,
No need to apogolise, I should have guessed you meant horizontal combinator IC402 since I had already replaced it earlier when we were debugging the short.
Here are the voltages for IC402:
PIN
Indicated Voltage (on the monitor schematic)
Measured Voltage
1
-
0...
Hello @Relayer and @BradtheRad,
The monitor filled the whole screen with "background light" on free run prior to me breaking it. This is why I thought there would be something still wrong with the monitor. However, lets try feeding the monitor a signal...
When I connect a rasperry pi to the...
Hello @Relayer,
and oh boy do I got good news for you!
Post office found the lost packet of replacement diodes for D467. I replaced TS467 along with D467. Finally the monitor starts up (very flickery video warning):
However, there is still some problem: the picture won't center horizontally...
Hello @Relayer,
and my apologies for the long wait. I have had practically zero spare time to work on this project in the past weeks.
I attached the light bulbs and the monitor as instructed. I also had D467 out of circuit in addition to TS467. The voltage rail measured correctly as 125.5...
Hello @Relayer,
and again thank you.
I have a generic question on this debugging stuff: How did you know to ask me to check TS467? I am asking this because my guess would have been any component thats attached to ground and the 125 volt rail, like R494, C494, R469, C469, D468, D467 and so on...
Hello again @Relayer.
D468 is a RGP10J diode which seems to be ok. The resistance from anode to cathode is 568 ohms with no reverse leakage.
D467 is a BY448 diode which seems to be broken. The resistance from anode to cathode is 586 ohms with reverse leakage around 285K ohms.
I will order a...
Hello again @Relayer,
I have good news! TS467 is faulty. TS467 is a Philips BU508A NPN transistor (https://datasheetspdf.com/pdf-file/1144968/Philips/BU508A/1). I measured it out of circuit and got the following readings:
B -> C 275 ohms
C -> B 275 ohms
B -> E 100 ohms
E -> B 100 ohms
E ->...
Hello @Relayer ,
There is a four wire connector on the PSU board. It has pins labeled from 1 to 4. On the schematics there are labeled lines (1M2, 2M2, and 3M2) coming from PSU from places like the cathode of D141, D142, and D143. These *M2 labels indicate the pin on the four wire connector...
Hello again @Relayer,
the replacement part for TS152 finally arrived and I replaced it. I measured M2 voltages again as described below
New voltages are:
Pin 1 measured 126V
Pin 2 measured 26V
Pin 3 measured 16V
Pin 4 is ground.
There is no noise from the PSU. We have finally fixed the PSU...
Hello @Relayer,
I tested TS152 and it seems to be faulty. TS152 is a PH BT151 500R thyristor (https://static.rapidonline.com/pdf/151290_da_en_01.pdf)
Resistance from Anode to Cathode is 3.5M ohms
Resistance from Anode to Gate is 3.37M ohms
No reverse leakage from Cathode to Anode
No reverse...
Hello @Relayer,
and again I am very sorry for making you wait.
I have a replaced D152. Cathode leg of D143 is no longer shorted, but the PSU still whines. Should I order a replacement for TS152?
Hello @Relayer,
replacement for IC402 arrived. I soldered it in and tried out the monitor. Only a high pitched noise from the PSU ensued. I then disconnected PSU from the monitor, wired the light bulbs from M2 pin 1 (M2 is the connector for the voltage rails) to the negative leg of C145, and...
Hello @Relayer,
and thank you once more.
I replaced D152. Short is gone from the cathode leg of D143! Replacement for IC402 is still in the mail.
Do you think it would be okay to test the voltage rails without IC402? Moreover, is it ok to try to turn on the PSU without connecting it to the...
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