Hi, I was hoping for some advice please. I have a Sony Handycam CCD TR-350E. I bought it in 94. I have many 8mm tapes i want convert but my batteries are not reliable anymore. I used to use the AC adapter to power device and connect to TV. Now i’m having trouble with adapter. When i attach it to device, then switch it to VTR DC out, the device turns on. When i press play, or rewind or even forward on device and all power cuts outs on both device and light on adapter. As this part is no longer available i would like to have it repaired but i’m not sure where to start trouble shooting.

Please help me as i really need to convert my memories off my dozen 8mm tapes to disc.

Many thanks

Hi Tony,

You need to make sure the adapter is working first. Have yo check the adapter output voltage? Is the voltage good?



Dear Jestine,

Thanks for the september issue of newesletter you send. Nice Tips for me. Jestine i destroyed my ring tester i short the probe from B+ to ground. Now it has no power. I think the IC was damage the part number is HCF4069UBE & HCF4015BE. Is this ic available in the market? Do i need to buy exactly the same of the letter after the number? Thanks…


Hi Berlin,

Sad to hear that just becareful on the next test. As for the IC The best is to use back the same part number. If you can’t find then you may need to do a trial on error as some different version of ic (although with the same part number) could not make the LED to go full bar.



Hi Jestine,

I’ll try to replace the KA7500C PWM IC. By the way what might be wrong with the inductor? It has 10 pins, 8 solder joint. Is it possible to test with the Blue Ring tester? I don’t know which pins to test.


HI Boling,
Actually i know of this problem even before the ring tester out to the market. Last time i repaired lots of ATX power supplies and could compare whatever parts. Usually when the output is not correct and all the components check to be good the toroidal inductor was the caused of the problem. Since at that time do not have the ring tester thus i just replaced and send it back to customer. Sometimes i wish i could see this kind of problem here so that i can use ring tester to check it out.

It will be tough if you do not have the same model for comparison. First you need to use ohm meter to check which pin to which pin then only you use ring tester. But again i do not know the good actual reading of ring tester since i do not have the meter back then. Track from the 5 volt output inductor pin to see if it shorted to the 12 volt inductor pin.



Hello Jestine
I have here a crt tv SANYO model: EC 20 MTN4 which has the following default:
presents a image very blue, I’ve swapped the transistors of the plate with the picture tubebut it was all the same.
You can tell me where is the problem?
Attached I send pictures

HI Ricardo,

It could be weak picture tube or the eeprom data already corrupted. If you know the factory code try access it. Or you can compare the R,G,B voltage and signal at the crt board. Any differences is the clue for you to troubleshoot it.



Check all output voltage stable but when i adjust screen at flyback voltage drop from 150v slowly to 130,120,110v and picture auto cut off and voltage up back to 150v. already changed flyback, ecap 160v 33uf & 160v 220uf and try to swap picture tube all still fail, all component at primary side already check all i think ok, just power FET still not try to change. using STR 5 leg.  In your ebook what method should i try ???


By right if you adjust the brightness or contrast the B+ voltage should have very little effect. i suggest that you directly replace the B+ filter cap and retest. If the primary side have e-cap (big or small) try replace those and retest.


Hi Jestine.
Today I repaired a smps with blown sec diode. It had two 3-pin TO220 diodes on heatsink. one was a common Cathode, and the other was a common Anode diode pair.
The common anode was completely shorted. The common cathode measured fine with x1 and x10 range on my multimeter.
Do I have to replace both devices or only the blown one?
Kind Regards

HI Riaan,

If you could find the original package then use it otherwise you can put in an external diode  (UF5407) but you must first defeat the shorted diode.



HI William,

I have a problem that i have been trying to fix on a wharfedale TV,the
picture is squeezed in from the sides EW. I checked components on the
horizontal section but most of them tested ok. i am not certain about
the geometry correction(pincushion) circuit.
Can u assist.

Could you locate the pincushion transistor? if yes then make sure the center pin have voltage. A lower B+ voltage and shorted modulation diode also could cause such problem.

Things are moving slowly on the Electronics workshop that i had
planned to open, as we are now flooded with cheap products, which are
impacting on repairs business.

It happens everywhere even in my country too. I suggest that you look for repair that have profit margin like the LCD TV, LCD Monitor and etc.



Hello Jestine,

There is one monitor whose HOT is shorting repeatedly. I have checked everything and supply voltage is normal for heater and others also. When i run the monitor without booter mosfet then it runs normally with full screen light. I have already lost 3 HOTs. What will be the problem if, i run without boosting mosfet.

I felt that when using the booster, the supply voltage becomes to high to short the HOT. All MOSFET related transistor and resistors are ok. I seek your proper guidance.



Hi Gopal,

It can be the problem of the B+ fet gate signal. It should have about 10 to 12 volt peak to peak. Check also for horizontal driver transistor that is located nearby horizontal driver transformer.




Hello Mr.Yong,

Thanks for the monthly repair newsletter, I appreciate it very much. I have something to refer to you regarding my monitor. It accidentally pressed the button of the monitor by my son resulted to be locked. My question is how to unlock the monitor. It so happen that the instruction is in Japanese language so I don’t know how to do it. The model of the monitor is I-O DATA LCD -A172V.Please gives me some information or instruction how to unlock the said monitor.

Once again thanks and more power to you.


Hi Renzi,

Different model have different way to unlock it. Try press one by one the button for more than 15 seconds and see if this help or not. Start with the menu button.


Hay Mr.yong i appreciate your help , i think god is
keeping u a live good reason.
Mr yong am working on LG flatron W2234s ,,this LCD displays normal
with no signal display but when iconnect it to a CPU it displays for
1 minute and turning light off and on continuously, its right side has
a 2 inch white line even if not connected on a CPU.
when i adjust the resolution and the refresh rate it also ad more time
to turn its light on and off ,
Mr. what could be the cause or the problem.
have nice time sir.
yours M.A.Yaaku.

Hi Yaaku,

Right side 2 inches can be the problem of bad LCD panel. Before that make sure all the output voltages are good and no losse connection in the cable.



Hello jestine gud day, I hope you’re always fine and in good health. Thanks again for all the  newsletter you have sent to me. I have some repair problems that I think you can help me. It is about a CRT tv 29 inches sharp the problem is the SMPS. Please send me some ideas on how to troubleshoot SMPS of this unit and what are the possible caused why this unit is not functioning. when in fact, I have already replaced the regulator IC, the oscillator IC and the opto coupler but still nothing happened. I hope you can help this problem because I know that you are the most knowledgeable in this field…. Thank you and God bless!!!

HI Tito,

I suggest that you follow the link below to isolate the problem:


because sometimes a shorted components in the secondary could cause no power in the primary section.



Hi Jorge,


I know that you are busy but I just wanted to say some things about testers.

First on your site you always advise about the Blue Ring Tester and Blue ESR meter. Now is it really true that they are good, because I bought one Blue Ring Tester and one Blue ESR Meter and One Atlas Peak Component Analyser from John Bachman (Ana Tech) and only the Atlas Peak Analyser is still working. Only 1 time I test using the Blue Ring Tester and it doesn’t work after that. Now I don’t know if I should buy another one.

So far i have sold hundreds of unit and no complaint about this. Even my unit already more than 3 years plus still working good! There are 2 ways why a unit would not work. One either bought a kitset and installed wrongly or have the meter tested on high voltage circuit that kill the ICs.


Second what is your advise, because I bought instead a Sencore Flyback Tester. Do you know if it is good, because I want something that don’t break down. The one I bought is at this site http://www.ebay.com/itm/190580516157?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649#ht_500wt_1054

I have heard of this unit but never use it before. Sencore product is usually reliable.


The last thing sir is that I have finally started working on my LCD Monitor Repair book that I bought and I am using a AOC 197-s Flatscreen that someone gave me, but I have no Schematic because I can’t find it. If you have it can you sell me this schematic. Because the site where I pay yearly for diagrams have none (Club de Diagramas). Thanks.  By the way this LCD Monitor light comes on then a screen with lines comes on and after 2 seconds it goes blank and the led light turns yellow. If you can help. And God bless you sir.


Sorry i do not have the schematic. As for the problem first, the output voltages have to be good and stable and no bulged cap. Next make sure there is dc supply voltage to the inverter ic. If the supply cut off after 2 seconds then most probably the MCU in the main board could be the cause. Again make sure first there is good supply voltage to the ICs in the mainboard.



good day sir,


i have a customer with sanyo color  21″  model AMV-2136 …

Problem: Dead on arrival

Remedy: After opening the Equipt. fuse is totally black(blown)

SOT is shorted(analogue tester checked)

I replaced fuse, SOT and Ceramic caps across the base.


I desolder 1 feet of all the primary components still bright light never goes off

I lift up center pin of SOT the bright bulb turns off ( I remove again the SOT check with Multitester but its good)

I return the center feet. and lift the primary side of Chopper Xformer…

Inquiry: since i still not finished assembled my FBT tester because IC is not available on my town..maybe i go to nearby city to purchase the components of FBT tester.

my question is could it be possible that culprit is the chopper X’former?

best regards,


HI Lito,

Usually power transformer will last long. If a fuse blown you can try remove the transformer and power on. If the new fuse blow again then you know is not the transformer fault. shorted posistor, bridge rectifier, power fet and power ic can cause the fuse to blow.


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