Magnavox LCD TV Repaired
A friend recently brought a Magnavox 37MF321D/37 into my PC shop with the complaint of “Won’t power on” She wanted me to take a quick look to see if it was an easy fix as she had already bought a new set and would use this as a spare if it was not too expensive to fix.
Upon initial inspection, the correct issue was power light blinks and TV attempts to turn on but does not. As I suspected bad capacitors, I proceeded to disassemble the unit.
After removing the main PSU board, I saw I was indeed correct. There was a bad 2200uf 35V , two 1000uf 35V and one 1200uf 35V as seen below.
Luckily I had a 2200uf 35V and the two 1000uf 35V from other boards. However I could not find a 1200uf 35V anywhere! Since this project had to be completed now or never (We are a busy PC shop and don’t have much room to set this aside and wait for parts), I had to come up with a solution. Knowing it would be a bad idea to replace a capacitor rated for 1200uf 35V with a 1000uf 35V (I don’t mind going slightly higher, but never lower than rated), I had to find another solution. Since I had a 1000uf 35V and a 470uf 35V , I decided to hook them in parallel and see what they read on a digital capacitor meter. The reading was about 1350uf so I decided to proceed.
As you can see above, I attached the two caps in parallel using solid hook up wire and soldered them in place.
After assembling the TV, the power turned right on. We let the set burn in for several hours and reassembled it. My friend picked up the set and it has been working well ever since.
Hope this article helps someone who may be in a similar situation.
This article was prepared for you by Matt Lipay from USA and he likes electronics repair.
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Waleed Rishmawi
July 5, 2014 at 3:35 pm
thanks for sharing. yes, sometimes we have to do that to make things work. if you find parts replace it..if can not, then improvise and make things work. good job on the repair. Happy forth of July.
haroon
July 5, 2014 at 4:43 pm
very nice and good job and very very good techniqe
Goh K S
July 7, 2014 at 9:51 am
The parallel capacitors mounted on the wires are mechanically not sound. The best is to get a 1200uF 35V cap, else just stick with the 1000uF and accept a slightly higher ripple.
wael fathe
July 5, 2014 at 7:29 pm
i dont recommend this method 2 caps near each other each one send
its heat to the near by cap it is heat the kills the electrolic caps and it is the heat the speed up the process of esr increase
not to talk about the long leads which will contribute to esr increase
randy warren
July 6, 2014 at 11:01 am
right on, Wael, I would never let something like that out of my shop, that is just asking for trouble sooner or later, look too much like a hack job that gives techs a bad rep....
Robert
July 6, 2014 at 8:38 pm
Will you guys ever send in any articles?
Mark
July 7, 2014 at 5:29 am
Well said Randy. NEVER GIVE THAT MESS TO A CUSTOMER! Better to go with only the 1000uF if the 1200uF is a 20% tolerance, and the replacement meters in at 1000uF or higher. Imagine the liability if that cap-stack falls apart and burns down the house. Crazy fixes must be limited to techs personal items.
Ogen-rwoth
July 5, 2014 at 9:25 pm
Very interesting piece of work.
Robert
July 5, 2014 at 10:10 pm
Good job Matt and thanks for the article. I would have put some hot-glue on the caps & wires to help keep them safe from vibrating loose.
Anwar Shiekh
July 5, 2014 at 10:33 pm
Nice, but as a customer I would have been happier with less of a hack.
Mark
July 6, 2014 at 7:25 am
Hey Matt, Good idea. I see that everyone has an opinion as to how things should be done, but when you don't have correct parts, it gives you a good opportunity to try something new. Yes, it is probably not the best, long term solution, but credit where credit is due. Good on you for thinking out of the box.
daniel
July 6, 2014 at 5:17 pm
Hi good job for testing but replace with original part before it goes to customer
Andrew
July 7, 2014 at 5:26 am
I really enjoyed this repair in so as i have used the same inginuity as mounting various substitutions also
Humberto
July 7, 2014 at 7:07 pm
Well, finally the LCD TV was repaired and Matt gave his own solution anyway, remember it's not easy to have a similar to substitute, he should analise positive criticals.
venu gopal
July 7, 2014 at 10:50 pm
good job.
but i think it won't make much of a difference if it is 1000 or 1200 MF.Mixing a big and small capacitor is not sounds that good for filtering.Just the 1000 one will do the job. Thanks. 🙂
Andre Gopee
July 7, 2014 at 11:08 pm
Good Job Matt... I personally think that you should try and get the original part but sometimes with time, parts availability and the customer request for a CHEAP fix, you did what you had to do. many people have their own opinion but I am sure somewhere along the line they were in the same situation... Good luck and Great article.
beh
July 8, 2014 at 1:00 am
Hi MATT
thanks for article .yes this is possible but no extra wire
is require just twist the negative pins of caps together
and also positives and push it in the hole of pcb
and solder it.it works .i have done this several times
no problem is found yet!
cheers
beh
Matt
July 8, 2014 at 7:55 am
This was a set that would have been trashed if it had not been repaired at that moment. It is not a production set and it was a solution discussed and agreed to by my friend. I would never charge for this type of repair and was just trying to show that in locations where parts may be hard to find, there are other solutions if you think outside the box. I am not a TV repair shop and just try to do favors when time allows. I appreciate all of the reasons why this is not a good idea!
beh
July 8, 2014 at 12:49 pm
MATT: this is done many time in the history of repair and has no any problem scientifically and electronically as well as theoretically is correct do not worry and ride on!
Taring K Arioka
July 9, 2014 at 6:20 am
Connecting two electrolytic capacitors together is a good idea. It is much better than doing nothing to the equipment brought in to any shop for repair.
Taring K Arioka
August 3, 2014 at 11:37 pm
It is good to learn new techniques to avoid seeking help elsewhere when the real problem is coming up for repair. Thank you for this nice article.
A.Baxter
June 25, 2015 at 1:16 am
For the critics:ask yourself: "does this deserve to be on the internet?"
I'll tell you, it DOES!
The helfpful admonishment was : "not mechanically sturdy."
Buy hey - its not like this is an electronic Tranpoline or anything....
Good one Matt.