R_J
Badcaps Legend
Last Activity: Yesterday, 05:26 PM
Joined: 06-28-2012
Location: ☻
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It's not a waste of time, good to hear you found the problem, I was going to suggest checking the windings, but they usually don't give a problem, this broken wire would cause the problem you were having. the NTC should be ok... -
There is no need for low esr for C40, Have you changed C33 and C36 as well? The voltage across C33 should be at least 20~25vdc, Q4 acts like a regulator who's base zener sets the voltage which is 15vdc, and Q4 emitter should be about 16vdc, This voltage is to maintain the vcc for the ic, if it is only 11 volts that may be why it is shutting down and restarting.
If you have not replaced C33 I would start, there. The Lvcc srtart voltage is min 11.2v and the turnoff threshold is around 10 volts If C33 is weak it will not charge to around 20v...Last edited by R_J; 02-17-2025, 09:38 PM.Leave a comment:
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What voltage do you have ACROSS C33 (47µf/35v) and ACROSS C36 (47µf/35v?
I would change C40 (1µf/50v) and check R49,50,51....Last edited by R_J; 02-17-2025, 06:50 PM.Leave a comment:
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Try a jumper wire between the two silver connections on the printed contacts, that should check if the actual input circuit works, and it is the printed switch that is the only fault...Leave a comment:
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The rubber button should have a conductive carbon impregnated in it, after time the button is no longer conductive, try recoating then with a conductive coating. They have remote control contact repair kits available where you can attach new conductive dots
You could try some alcohol to clean the rubber contact and the board but do it lightly or you could remove any carbon left on the button and the printed trace on the pc board
I have repaired many remotes with similar problems. they have ways to do it now, just enter "remote control button repair kit" into google You can...Last edited by R_J; 02-05-2025, 08:31 PM.Leave a comment:
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Pins 7 and 8 are marked as NC (No Connection) look at the pin def. Pins 1,3,5 are VLED1_+ (from supply C8108/9) pins 2,4,6 are VLED2_+ (from supply 8209/12) All the other pins 9~24 are returns (led-) All 14 separate FB circuits have a mosfet and a source resistor as return to ground, each mosfet source also has a return (current Sense) back to the controller so it knows if a single string is open and likely shuts down all. Also the leds are controlled by the video that is displayed on the panel.
You likely have bad led's or maybe bad connections in the panel between the led strips and distribution...Last edited by R_J; 02-01-2025, 11:51 AM.Leave a comment:
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Likely made by Amazing Microelectronics, a close marking code is AZC399-04S.R7G (C30xy)Leave a comment:
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It is a simple transformer; do you have line voltage on the primary? do you have 14vAC on the secondary? What is the resistance of the primary winding and the (center tapped) secondary ?Leave a comment:
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Are you sure it is 2 & 5 for the driver pins and not 2 & 4 ? if it is 2 & 4 it is Likely a Richtek RT8110B...
Last edited by R_J; 01-21-2025, 06:56 PM.Leave a comment:
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I see you are working on two vcr's, The JVC vcr has a SMPS, after looking at the service manual for the panasonic, C1003 is just for the linear power supply like stj said. so no need for low esr...Last edited by R_J; 01-18-2025, 10:51 PM.Leave a comment:
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That is because pins 3 and 4 are not referenced to ground, check the voltage between pins 3 & 4, it is likely correct (it likely fees the vfd heater pins)...Leave a comment:
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ok, I had another look at the service manual and I see the feature box, I could see bad capacitors effecting the video qualityLeave a comment:
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Have you tried a Master Reset?
To perform a factory reset on a Yamaha PSR-230 keyboard, you can do the following:[LIST=1][*]Turn off the keyboard[*]While holding down the [+] and [-] buttons, turn the power on[*]Release the [+] and [-] buttons when the top of the screen displays "Clr All!"[/LIST]Here is the Yamaha link [URL="https://faq.yamaha.com/usa/s/article/U0001936"]PSR230 Factory Reset procedure (yamaha.com)[/URL]
Also check:
If your Yamaha PSR-230 is not producing sound, you can try these steps:[LIST][*][B]Check the headphone jack[/B]: Make sure...Last edited by R_J; 01-08-2025, 06:14 PM.Leave a comment:
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So the problem was with the input source (feature box), NOT the tv?...Leave a comment:
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Thats not 738 it is likely 73B which is a 5.62kΩ 1% [B]EIA-96 Series Resistors[/B]Thats not 738 it is likely 73B which is a 5.62kΩ 1% [B]EIA-96 Series Resistors[/B]Thats not 738 it is likely 73B which is a 5.62kΩ 1% [B]EIA-96 Series Resistors[/B]Last edited by R_J; 01-04-2025, 05:09 PM.Leave a comment:
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This might be the part VCHW084T-R22MS5 check the dimensions...
Last edited by R_J; 01-04-2025, 12:39 PM.Leave a comment:
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I marked the first dot just to view the vote so I voted for windows 11 by mistake, I use windows 7 mostly and windows xp for somethingsLeave a comment:
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Do you know if the signal is being lost in the preamp circuit or in the power amp circuit? If you do not know, try connecting a jumper wire between A and C on that plug and see if you get audio from both speakers, if you do then the fault is not with the power amp section.
Are you using the internal speakers or external speakers? if internal make sure both external speaker connections jumper straps are connected to the center screw and all three screws are secure.
Most problems like this on old stereos is caused by oxidized switch contacts or controls.Last edited by R_J; 01-01-2025, 09:40 PM.Leave a comment:
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Check that you don't have a short on the 5vstby output, check that D101 is not shorted, it is a dual diode so check it in diode mode between center pin and each of the other two pins. D101 actually supplies +12v to that small standup board PWB1 which I believe supplies the standby 5v
J29 should be cold ground and J28 should be +12v check that there is no short between these two jumpers, and if there is no short, check what voltage you get across the two jumpers.
Are you getting any voltage across E107 this is the vcc voltage for U101, there is a zener diode in that circuit, ZD101 and...Last edited by R_J; 12-29-2024, 05:28 PM.Leave a comment:
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