JVC HM DH30000U power problems

[Jpass992]

Hey all, I know that I haven't posted in a while, but I have a problem with an 8 year old JVC HM DH3000U that hasn't been used in a while. It had been plugged into a wall sitting idle for so many years. Recently, family had just bought a new TV and had unplugged all components. When setting everything up, I plugged in the JVC HM DH30000U, and I would hear the fan spin up for a few minutes, and the Digi Picture and S-ET indicators light up but then after a few seconds, they would go dead. There was no power to the fl display at all. Pressing the power display did nothing at all either. The strange thing is that even after the fan has stopped spinning, there is still the red light coming out of the optical output, so I know that the unit is getting power. What would be wrong? The unit is practically mint with all original stickers on it as well. I have the service manual for the machine, but would not no where to start. I hope that this is an easy fix, as this machine has really only seem use from 2003 - 2005 and was tested ocassionally by myself as to make sure that everything was working still. Oh, and by the way, Merry Christmas to all!!!

[kpmedia]

I thought about this for a few days now. I have an S-VHS VCR in similar condition.

The VCR was likely harmed by a power surge. This sometimes happens when plugging in equipment, and you'll see/hear a spark of electricity at the plug. That's not good. It's rare, so I still preach the practice of unplugging unused equipment (when it will stay unused for a few weeks minimum).

Some of the capacitors on the power board may have fried. Open the deck, and look for bulged or leaking caps.

See the images here: http://www.digitalfaq.com/forum/home...html#post13029

[kd0hdf]

I have been having the same problems with my unit. I have dissambled the power supply and found no bad capacitors. Any ideas as to what else this could be? Do you know where I could get the service manual for this?

[NJRoadfan]

Bad capacitors are not always visibly leaking or bulging. The only way to test them to see if they are "good" is to de-solder them and test their capacitance using a specialized meter for the task (multi-meters don't do a good job). You can only get an accurate reading of capacitance by taking the capacitors out of the circuit. Blown ICs and voltage regulators can also cause power supply issues. Also don't forget an overlooked but easy fix, a blown fuse.

A good first start in diagnosing dead equipment is finding the service manual and testing voltages coming out of the power supply. The proper voltages (relative to chassis ground) at various connectors/plugs are usually labelled on the schematic diagram.

[Blatte]

Hey guys,
I recently got the same dvhs deck and I have exactly the same problem ! Old age issue ?
As suggested by NJroadfan, I bought the service manual and a capacitance tester.
Let see if the problem is easily fixable (I'm not an electronic technician at all !), but de-solder a component and test it, I think I can do it
@kd0hdf: the service manual is foundable on "servicemanual.net" for 16 bucks.

[kpmedia]

Quote:

Originally Posted by Blatte

@kd0hdf: the service manual is foundable on "servicemanual.net" for 16 bucks.

Post it here and share.

servicemanual.net is a dead page. It goes to a squatter domain.

Even if it did load, know that sites like those are just scam sites, selling manuals illegitimately. They're not an "authorized" seller or anything of that nature. They just found a bunch of PDFs and try to milk money from others. We find that behavior to be rather disgusting. One of the goals of digitalFAQ.com, for the past year (since 12/2010), has been to archive as many user manuals and service manuals as possible. Our downloads are free.

More on that here: http://www.digitalfaq.com/forum/vide...s-service.html

So upload the PDF for us.
If it's larger than 8MB, put it at a free Dropbox account, and I'll download it, and then make a home for it here.

Thanks.

[kd0hdf]

You can read it the service manual here: http://www.scribd.com/doc/49803734/JVC-HM-DH30000U but I could not download it as I don't have an account on scribd.

[Blatte]

Quote:

Originally Posted by kpmedia

Post it here and share.

servicemanual.net is a dead page. It goes to a squatter domain.

Sure, it's servicemanuals.net, with a s.
Funny, because, I never found any service manual for free and always had to pay for it.
I'm not even sure than a service manual is supposed to be released for customers (that could explain, why it's always a pain to find).

So too late, I paid for it...... but why don't share it with the community. It could even worth a premium user update

It's larger than 8mb, so check your pm

[kpmedia]

Added: http://www.digitalfaq.com/forum/vide...-dh30000u.html
Indexed: http://www.digitalfaq.com/forum/vide...s-service.html

Thanks very much.

Quote:

Originally Posted by Blatte

Funny, because, I never found any service manual for free and always had to pay for it.
I'm not even sure than a service manual is supposed to be released for customers (that could explain, why it's always a pain to find). So too late, I paid for it...... but why don't share it with the community

At one point in time, manuals were only available to authorized service centers. Through the years, however, as JVC no longer supported these aging VCRs, manuals were released online both by them and by the repair community. As that community has shrunk -- See many VCR repair shops lately? -- the PDFs have been found "in the wild" on various websites (freebies like the now-dead Geocities.com, etc) and forums, usually shared by former broadcasters, video educators, repairmen, etc. PDF scrapers foraged the web for PDF files, much like email spam harvesting bots, and somebody in some foreign country (usually Russia, China, Pakistan) sorted them, slopped up an ad-filled website, and decided to gouge people with a pay access website.

That's NOT in the spirit of the initial sharing that even put these manuals online.
So every manual we can add here is one less dollar given to those unethical opportunist shysters.

That's the main reason downloading files and images from the forum requires a Free Member (minimum) account. We don't want to piss away bandwidth (thus bogging down site speed) so that scrapers can forage for files. These files are provided for the legitimate media community (both professional and consumer/amateur/hobby), not the online abusers of the world.

Quote:

Originally Posted by Blatte

It could even worth a premium user update

Premium membership is one of the primary ways this forum is funded.

And at $20, it's not even expensive: http://www.digitalfaq.com/forum/news...oin-forum.html
Just enough to help offset costs.

[dad2]

Bad capacitors are not always visibly leaking or bulging. The only way to test them to see if they are "good" is to de-solder them and test their capacitance using a specialized meter for the task

You don't have to remove capacitors from a circuit board to test them, read about ESR testing at this link:
www.repairfaq.org/sam/captest.htm#ctesr

Look under "Equivalent Series Resistance (ESR) and Related Parameters".

Using this method is very reliable and easy, and will save a lot of time and a few circuit boards from being damaged.

[kd0hdf]

So I built a circuit to test for bad capacitors out of an 555 timer. Everything that I tested seemed to be working normally. Is there anything else that I should check?

[dad2]

If the fl display is dead I'd check the minus 29 volt (-29v) pin 2 on CN7005 on the power supply board, if missing or low check D5209, R5317, C5209, R5315, and D5311. If the fan spins the fuse is fine. This power supply has several inputs and outputs, most supplied by one transformer, any one output could have a problem, but a dead fl display tube at least indicates a missing -29v. If you have a -29v from the power supply then check for it also on the fl display board right up to the correct pin on the display tube.
Are you sure the cap tester you built is working correctly, do you know how to use it? For cap tests in circuit, make sure that the unit is unplugged for a while, even then short-circuit the larger caps in the P/S unit to completely discharge them before testing. Use the ohms range on your multimeter for the resistors, diode check for diodes, DC voltage range for DC volts.

[Blatte]

Hey guys,
In my case, after having checked every caps on the power supply PCB , I changed these (got from mouser.com):

33pF, 1kV
C5103

100uF, 10V
C5310
C5312
C5314
C5316
C5318
C5320

4,7uF, 100V
C5208

18uF, 50V
C5209

470uF, 10V
C5301

330uF, 10V
C5303

Now, the VCR turns on well.
Input/output video and audio signal on TV OK
VHS playback, audio/video perfect
DVHS playback, video perfect, audio very low
No digital audio signal (the fiber is red lightened) either.
The problem comes from the Digital PCB. I switched with the one from my other (working) 30000U deck and it worked fine.
The problem with the Digital PCB, it's "digital very small" electronic. I don't have the tools and (first of all) the knowledge to fix that kind of stuff.
If anyone has some good tips, that would be cool

[NJRoadfan]

A quick peek in the service manual shows some caps on the audio board. Weak/no audio is a common sign of bad caps. I'm guessing that its all surface mount parts on that digital board? There are techniques for replacing surface mount parts, but it can be tricky and it requires a steady hand. Does audio work fine via firewire?

[Blatte]

As I said, the audio works fine by playing a VHS tape (so by using an analog source), the VCR audio card is good
The sound is very low only by playing a DVHS tape.
Yes, surface mount on the Digital PCB, so that's gonna cost more to fix than buying an other deck :-/
I think my repair session is done for this deck, raaa, so close.
There is a way to get the sound via firewire ?
I've never been able to get any output audio/video signal from a 30000 U.
Btw, is this model dv out ?

[NJRoadfan]

Quote:

Originally Posted by Blatte

There is a way to get the sound via firewire ?
I've never been able to get any output audio/video signal from a 30000 U.
Btw, is this model dv out ?

The deck outputs a MPEG2 Transport Stream. As long as the content isn't marked protected, you can use a computer to view/capture your tapes. Windows has drivers built in, so just plug it in. You can use VLC to view tapes and CapDVHS to capture them.

[Jpass992]

Hey everyone. I just opened up this machine and checked one of the fuses and it seems to be fine. This machine isn't mine, its my fathers and he's wants to get this machine repaired. Can anyone on here recommend a good reputable repair place?

[lordsmurf]

Quote:

Originally Posted by Jpass992

Hey everyone. I just opened up this machine and checked one of the fuses and it seems to be fine. This machine isn't mine, its my fathers and he's wants to get this machine repaired. Can anyone on here recommend a good reputable repair place?

Jots Electronics in Dallas, Texas (actually Arlington, but same difference).

Mention that you were referred to them by digitalFAQ.com, if you do -- we like letting them know we're sending them business.
Excellent reliable repair shop -- even better than factory repair centers. (Factories used to outsource to them, in fact!)

[johnharbo]

I have the exact same problem with two of these units. Suddenly, no power. I don't have the time or patience to try to fix. If anyone has figured this out and would like to have my two units, you can have them for the cost of shipping.

Other than this problem they are still in great condition, and probably have only been used less than 200 hours each.

[kd0hdf]

I would love to try to fix your units. Could you contact me at kd0hdf@gmail.com?