Re: Add Stereo Input To Hi-Fi (Sony SONY PMC 107L)
Can i solder the negative wire to any suitable ground on that main board.
Eg: On the volume control ground marked blue circle in the jpeg?...
Tarot Superstars
Senior Member
Last Activity: 11-15-2023, 06:08 AM
Joined: 08-14-2023
Location: England
-
Re: Add Stereo Input To Hi-Fi (Sony SONY PMC 107L)
Thanks everyone.
Where do i connect the negative wire?...Leave a comment:
-
Add Stereo Input To Hi-Fi (Sony SONY PMC 107L)
Hi.
I bought a Cheap HIFI to use as my PC output and speakers and forgot to check if it had an input. It doesn't.
Is there any way to add a stereo input. I have a bunch of Phono sockets I am not using.
Where in the circuit is the best place to solder the 3 stereo input wires?
This is the model and schematics:
[url]https://www.manualslib.com/manual/915495/Sony-Pmc-107l.html#manual[/url]https://Hi.<br /> I bought a Cheap H...o add a stereo -
Re: Short Circuit tester
I quoted the voltage incorrectly. It's 3 x 1.5 V batteries in series....Leave a comment:
-
Re: trying to fix a 6V 0.5A T1 (Transformer) AD050120T2 power supply
Hi.
I intended to do some temperature and frequency measurements.
The circuit had some more damage to traces and I attempted to repair them.
However, when i powered on the circuit for the second set of measurements, there was a short, open circuit, or other issue.
R0, R8, and Q1 were damaged. R0 is open circuit, R8 is open circuit, and Q1 is short circuit.
On the first set of measurements, there was no frequency measured (possibly because of an open circuit trace)....Last edited by Tarot Superstars; 10-08-2023, 02:10 PM.Leave a comment:
-
Re: Learning to fix a 6V 0.5A T1 (Transformer) AD050120T2 power supply
Thank you.
The advice on using a 12V power supply is very helpful since that would make it safer. I have a laser pointer thermometer and protective goggles, and the thermometer that measures up to around 400 C, and can measure the temp on U1 when I get it wired up.
I have a universal 12 V supply but I am afraid if I connect this to U1 it will break. Are you sure I can connect this adaptor to U1 VDD and ground and not break it? I might prefer 1 or 2 last mains powered...Last edited by Tarot Superstars; 10-04-2023, 03:34 PM.Leave a comment:
-
Re: trying to fix a 6V 0.5A T1 (Transformer) AD050120T2 power supply
Thank you. So, the then R1 and U1 wires 1 and 5 are acting as a voltage divider. R1 is 2.4 MR and U1 is 62 R so it takes less voltage. But it should take more if it were working I think.
Thanks for the link.
I'm glad that I found which componet was broken. The purpose of this was to learn about basic electronics fault finding, and I think I learned some theory and practical....Leave a comment:
-
Re: trying to fix a 6V 0.5A T1 (Transformer) AD050120T2 power supply
Thank you.
You are correct it was a little bit of a risk.
I did check min and max input voltage of Q1 and it's 2 V to 4 V, so 3 V should be ok.
Also, I checked that, when Q1 is powered up, source to drain is supposed to be almost no resistance, so bridging is similar to no resistance.
I checked the junctions of Q1 after and they are fine with no short circuits.
I used wires, croc clips, wore an insulated jacket, and heavy duty rubber gloves, and wasn't anywhere...Last edited by Tarot Superstars; 10-02-2023, 10:34 AM.Leave a comment:
-
Re: trying to fix a 6V 0.5A T1 (Transformer) AD050120T2 power supply
U1 VDD to U1 ground resistance measures 61.9 ohms.
Incidentally U1 VDD to the near side of D4 measures 62.5 ohms and continuity.Leave a comment:
-
Re: trying to fix a 6V 0.5A T1 (Transformer) AD050120T2 power supply
OK. We are heading towards trying to verify if U1 is broken. By measuring VDD to ground of U1. I don't want to desolder U1 to test resistance to avoid damage.
I have performed some more tests.
[B]Theory[/B]
1. If Q1 (mosfet) is not working, it won't switch on the source drain voltage and no current will flow to the primary coil. If it is working it will switch on current to the primary coil.
2. If I bridge Q1 source to drain with a wire, Q1 will be permanently...Last edited by Tarot Superstars; 10-02-2023, 06:48 AM.Leave a comment:
-
Re: trying to fix a 6V 0.5A T1 (Transformer) AD050120T2 power supply
I mean voltage going through the transistor source to gate, not parallel with it (possibly only going through the multimeter)....Last edited by Tarot Superstars; 10-01-2023, 04:33 PM.Leave a comment:
-
Re: trying to fix a 6V 0.5A T1 (Transformer) AD050120T2 power supply
I previously measured voltages across source and drain of the mosfet Q1 with power on. But this doesn't tell me if there is any real connection between those two wires (which there should be) because I have really just bridged those two points and the voltage could be going to those two wires but not through Q1.
I am going this route because I am wondering why I have voltage across Q1 but nothing on the primary coil. There must be some open circuit or it's not switching on or something. So, I am trying...Last edited by Tarot Superstars; 10-01-2023, 04:57 AM.Leave a comment:
-
Re: trying to fix a 6V 0.5A T1 (Transformer) AD050120T2 power supply
Thanks.
How did you come to the conclusion that there is a short circuit in the capacitor, diode, IC or that R1 is open circuit?
Also If i remember correctly R1 reads 2.4 mega ohms....Leave a comment:
-
Re: trying to fix a 6V 0.5A T1 (Transformer) AD050120T2 power supply
I don't have much experience, so I don't know what exact values I should be seeing. If the voltage is coming through a resistor or a SMD capacitor at either end of wires 1 and 2 of U1 or is part of the U1, Q1 stage or primary coil stage, and I bridge it, then I know that isn't what caused U1 or Q1 to read low voltage or incorrect voltages or pulses. It would be wrong of me to assume the IC or mosfet is broken if one of the connecting resistors is short circuit or open circuit.
What ohms?...Last edited by Tarot Superstars; 09-30-2023, 02:36 AM.Leave a comment:
-
Re: trying to fix a 6V 0.5A T1 (Transformer) AD050120T2 power supply
[COLOR="Red"][/COLOR]I have reversed engineered some of the stages and marked them in the photograph (Reverse Engineering.jpg).
[B]Primary Coil Voltage Tests After Re-bridging R2 and Bridging SMD Cap near primary coil[/B]
(See Photo: Test Setup.JPG)
I rebridged R2 (yellow circle), and bridged the SMD capacitor with a ceramic through hole capacitor marked (10 000 pF) (yellow circle). I measured voltage on the primary coil (red circles).
[B]Result [/B]...Leave a comment:
-
Re: trying to fix a 6V 0.5A T1 (Transformer) AD050120T2 power supply
How do you know U1 wire 1 to 5 is supposed to read 15 Volts? Is that from the block diagram on the data sheet (that says 9.5v/15.5v VDD?
[url]https://datasheetspdf.com/pdf-file/1319779/SiFirst/SF5920S/1[/url]
I was wondering if this circuit has a separate standby/start up circuit and is it possible the voltages are from this?
Could the start up section be broken?
Is that part of the circuit inside the IC?
Also, I could take a reading directly across R1....Last edited by Tarot Superstars; 09-29-2023, 03:03 AM.Leave a comment:
-
Re: trying to fix a 6V 0.5A T1 (Transformer) AD050120T2 power supply
Thanks.
So are you sure now, that U1 doesn't work?
What are the pulses from the gate and the mosfet?
What are the power readings on the mosfet Q1 if that's not what should be powering the primary coil?
Also,
I have just put together a current limiter using a 60 W filament bulb, as one reply suggested and I was planning to do it.
When I plug in this power adaptor the light bulb doesn't go on. I didn't test if the adaptor had power,...Last edited by Tarot Superstars; 09-28-2023, 05:33 PM.Leave a comment:
-
Re: trying to fix a 6V 0.5A T1 (Transformer) AD050120T2 power supply
I scratched both sides of the solder on R2 with a needle after it did not read anything. The reading I gave on this forum is after scratching the solder. No continuity on R2 and not reading a resistance. Only resistance was F1 ~12 ohms nearby.
After disconnecting one wire of the Bridging 200 ohm resistor, there was new solder left on R2 contacts and again it read no continuity and I read ~12 ohms from F1 and not the 200 ohms I was looking for.
Though I have not read wire 1 (ground)...Last edited by Tarot Superstars; 09-28-2023, 12:57 PM.Leave a comment:
-
Re: trying to fix a 6V 0.5A T1 (Transformer) AD050120T2 power supply
There is an SMD 200 R resistor in circuit and I tested a 200R through hole resistor out of circuit.
The 200R through hole resistor tests continuity out of circuit.
The SMD did not register continuity until I soldered the 200R through hole resistor in parallel.
But you think it's not faulty and that at the size it won't measure resistance until it's larger than 200 R.Leave a comment:
-
Re: trying to fix a 6V 0.5A T1 (Transformer) AD050120T2 power supply
Hi I have done another series of tests. I haven't measured 1 to 5 voltage.
Yesterday started measuring the mosfet voltages with power on. I am not sure what Gate source and drain are but it seems the gate is connected to the gate of U1.
I have included illustrations of the wires of the mosfet that I measured anyway.
Imagine looking from above the mosfet and the flat side is facing towards the floor.
[B]Results[/B]
[B]Illustration 1. Measuring from...Last edited by Tarot Superstars; 09-27-2023, 05:58 PM.Leave a comment:
No activity results to display
Leave a comment: