Andy's Techie Stuff

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There are a couple of know issues with this series of DVD recorders. Intermittently there may be a display flashing 'LOADING' constantly or problems with flashing green lines on picture or distorted sound.

Andy

I might be experiencing these. Unit is 8 months old. Recently had a couple of episodes of "crashing" where only remedy was to disconnect power (I know, but nothing else responded). Loading would then take anything up to 10 minutes. Sound issue is that sometimes the unit records a programme with no sound!

Just today picture distorted with wavy lines, black screen etc but still with sound. Do these sound like symptoms of the known issue?

Also, do the HDD's ever need de-fragged? If my PC was doing this I'd put through a defragg to clean up the HDD then re-install the software. Do these units benefit from firmware upgardes at all?

Grateful for any info and can supply serieal number if it helps


Rhymemaker

If the unit is only 8 months old, it should already be modded. There isn't a definitive way to tell. I'll check my list tomorrow to see if there's anything specific to look for. I know there's a version number handwritten on the micro pcb that will tell you if the mods been done during production. (3A, 3B 3C -early vers--- 3D-F modded) Also the first 4 digits of the serial will tell us the batch no., so I can compare that against those I have sold and the dates we purchased them (also state what model it is)

The symptoms of 10mins loading can be attributed to the problem, as can distorted recorded sound (although I've not had 'no' sound , it is possible). The picture is usually broken up with green flashing lines, which change as you open/close drawer etc.

The unit may have a way to defrag, but we have no info confirming/denying that. The OS in use is application specific, and there's no tech available.
AW

Thanks for replying Andy.

The broken picture only happened yesterday which prompted me to search for known issues before I contacted supplier so I would be better informed. I didn't see it myself although my wife desribed a black screen, wavy lines. She was able to turn the unit off but had to do this twice before system corrected itself.

I'll check the serial numbers and post back this evening - model is a DR-MH20.

Unit has been behaving itself since the above, until now that was. The unit is just over a year old and so out of warranty...!

It froze after deleting a recording. Had to disconnect power and tried to re-start. Unit reloaded after about 20 minutes of flashing. operated Ok whilst watching a recording.

Deleted said recording and same thing happened in that it froze. Unit now continuously flashs loading and will do no more.

Anything I can do?

Many of these machines are now coming up with the 'Loading' problems even though they have been modded.

The problem stems from the power supply running hot and many of the electrolytics are bulging/leaking. The hot summer seems to have brought on the problems.

Luckily its not a major problem and once the power supply is recomponented, they seem fine.

recomponented

what components? is there a manufacturer kit?

I have this sound fault!

I moved the unit to have a look and when I switched on, the PSU exploded!

The main culprits are the 1600uF/2200uF brown electrolytics in the power supply. Its easy to tell which ones... they have a pressure bulge on the top lid! They run very hot.... they are 105deg components, but still fail as a result of being worked hard. They dry up and then fail to smooth the supply rail to nice DC, hence causing various symptoms. There probably is a kit, but I just buy high spec replacements in bulk bags.
One nasty side effect can be that when unplugged and allowed to cool slightly, they then appear to be a high load on the psu, and the psu fails to regulate properly..then bang.. :evil: .I've seen that a few times. (Its also quite common on lots of other makes of things like early Sky digibox etc)

If you're lucky, just the main STR IC has failed.... if not then a few other comps will have bitten it around the STR....then its a bit more specialised a repair.!

You need also to make sure that on the under side of the main processor (silver can- plugs out) there are 2 resistors fitted piggy back (just off centre of the board)... one is for picture flashing.. the other for sound crackle.

Sort all the above out and perhaps every couple of years change the 3 main electrolytics that bulge.. and you'll have a reliable machine :D

Andy

I will change the electrolytics...but none have a bulge or look stressed

...but the two piggy back resistors are not there.

Model: DR-MH30SEK
Serial: 080B0112

Can you tell me their values and where they connect to?

Dave
I have a diagram, cost ?10 from ManualsParadise.com
Also lots of resistors and PCB track has vaporised!

email me at

service@wilkinsons.tv

I have some more info
AW

i have a JVC dr-mh30sek and when i plug it in i get no picture, the DVD and HDD buttons light briefly then switch off and it says loading and the drive flashses blue.

when the DVD player is saying loading none of the buttons work. i pressed black eject button on the drive itself (just visible if you open the flap and look down on the right) it still doesn't open which makes me think it might be a power supply problem but i can hear the HDD spinning.

There were 2 16v 470uf capacitors which had bluged/leaked which i replaced and still got nothing. The big brown capacitors do not look burnt/bulging/leaking. is it worth replacing them? what else can i do?

Even if they are not bulging etc, I would change them, since they allow the voltage rail to 'ripple' causing the crashing.

Check you have +5v and +12v on the HDD

If you have an oscilloscope, check for ripple as well.

yes i have 5v and 12v on the hard drive but i dont have an oscilloscope. i'll wait for the replacement capacitors to arrive then post my results.

i havn't got the capacitors yet, but i was looking at the 2 resistors soldered on the bottom of the processor board and checked them with a multimeter and got different values for them even though they have the same colours. what value should they be?