JVC Camcorder - Temperature low issue - Anyone know how I can get around this? - Page 1
Forum section: electronics / general

author: GabYoung92
author_rank: Regular Contributor
timestamp: November 07, 2012, 09:41:51 am
content: Hi all,I was given a camcorder, JVC MG330RAA which is having issues.The unit would not boot at all it was found that there was a direct short between the battery terminals. I removed the reverse protection diode and it started to work. Tested the diode, yup it was gone.Alright! The unit now boots, however... When It comes on (which takes a while to do so) it reports that the temperature is too low, please wait. (20 mins doesn't seem to be enough?)Giving a quick google search reports that it is a common problem due to hard drive failure. The HDD doesn't spin up (No spin up sound) and I did notice an error on one boot "HDD ERROR"It has a MicroSD slot which I would like to use.. The units image sensor does work as when the temperature message comes up, I can zoom and focus. (Picture of error message shows my laptop and reflection of LED strip lighting)Now, does anyone know if it is possible to bypass the temperature sensor, or to get it to ignore the HDD if this is the issue?Thanks

author: amyk
author_rank: Super Contributor
timestamp: November 07, 2012, 10:18:14 am
content: Try to find the temperature sensor on the board and heat it up. It might be preventing the HDD from spinning up when it thinks it's too cold to avoid moisture damage, but I don't think it should say HDD error...What type of hard drive does it have? If it uses a standard interface it might be possible to replace it with an adapter that takes a CF/SD card, or even an SSD.(A quick Google shows that replacing drives in camcorders is not as common as you'd think, probably because this is consumer equipment.)

author: GabYoung92
author_rank: Regular Contributor
timestamp: November 07, 2012, 10:57:46 am
content: I've looked over the unit and can't really locate the sensor.The room which I am in is 28.2 Celsius, and the unit itself is 37.8 Celsius after running for a bit, so it isn't cold.The harddrive is a ZIF socket (samsung hs031GA)Having the hard drive completely unplugged does the same thing as when its plugged in.. nothing.Bugger, I've got a feeling that it requires a working hard drive... and I think the one it has, has had it.

author: tom66
author_rank: Super Contributor
timestamp: November 07, 2012, 11:54:43 am
content: Many SMART based HDDs have built in temperature sensors. If the drive is faulty, it could be reading back a zero or incorrect temperature, and using that as its temperature sensor.

author: Fraser
author_rank: Super Contributor
timestamp: November 07, 2012, 11:59:02 am
content: Hi,If I may comment on this scenario.I think you need to ask yourself what is the 'cause and effect' here..........You are given a camcorder and discover that the reverse polarity protection diode is short circuit........ ask yourself if that is likely to be a normal failure. I would suggest that the camcorder was connected to the wrong power supply and it was subjected to a reverse polarity supply.If we take reverse supply polarity as a start point.... the diode tried to save the camcorder and died in the act (what a hero!). Thankfully it died S/C and not O/C.Now ask yourself how much damage could have been caused by a reverse supply event. I can't answer that for you but you might be unpleasantly surprised !I would suggest that your faults might have more to do with damaged microcontroller than the sensor or hard disk. If the hard disk is in fact faulty, it is an odd coincidence that the temperature sensor is also in 'alarm'....unless the temperature sensor that is used is the hard disks on board sensor (many new 'smart' hard drives can tell their controller what their temperature is). If the system needs a hard disk in order to complete its self diagnostics on boot, you are likely to need a new or used hard disk in the camera. The OS expects to see certain interfaces on boot and if one is not responding to its polling it is likely that it will not play ball until the fault/error is corrected.Consider also what components would normally be monitored for temperature. In tape camcorders the tape deck was vulnerable to condensation induced tape grab with resultant wrapping of tape around the headThe imager chip and lens can also be vulnerable to condensation if a cold camcorder is run and begins to warm up. In a modern digital camcorder I would expect the imager chip/lens assembly and the hard disk to be the items requiring temperature monitoring.In your scenario I would normally remove the hard disk and test it to eliminate it from the investigation. Next steps would be to attempt boot without the hard disk to see how the camera behaves. If a hard disk is required to boot, I would source a used disk to fit or look into whether a CF Flash to Hard disk converter could be used. (if the temperature sensor on the hard disk is needed this will not work).As a technician you always need to ask yourself...1. what are the fault symptoms2. What is the likely instigator of such sumptoms (also ask the customer what they did or when failure occured)3. If available look at the schematic to find any common denominator for the fault.At this point all you have done is tested the appliance....no disassembly required.4. Dismantle the appliance carefully and take specific readings such as power supply rails etc. Make a note of all readings.5. If a component is found to be faulty, fit a new one and repeat all tests looking for symptom change.6. If the OS highlights a failure....look for the common denominator with the part and the symptoms.7. If the reported part looks to be a possible common point of failure for the fault symptoms....fit a new oneand so on........This is just a very condensed fault tracing method and there are others for different situations.I do not think you should chase the temperature sensor fault until you understand what you are looking for and why.....the OS can give you misdirection if you do not have the service manual to interpret the reports correctly. Many units use the same fault report for differing actual physical faults !Its a bit like car ECU diagnostics that provide a whole list of failures.....you have to look at cause and effect or else you will be chasing your tail and will not find the cause until many components have been replaced.Just my 2 cents worth.Fraser

author: Fraser
author_rank: Super Contributor
timestamp: November 07, 2012, 12:19:51 pm
content: As a follow on to my last message.....I know it is defeatist and no fun but you have to carefully consider the true value of an appliance Vs the new/used parts cost Vs the risk that it becomes a write off due to multiple failures. Many appliances that have received reverse polarity or overvoltage damage fall into the 'Beyond Economic Repair' (BER) category.I purchased an as new, in the box Panasonic SDR-H20 30GB HDD/SD Hybrid camcorder for GBP35 last month on ebay, complete with all accessories and original purchase receipt for over GBP400 !Consider whether you are trying to repair this unit for fun or for use....if it is the first then fill yer boots and enjoy the challenge (as I do regularly). If it is the latter, put the camcorder in a box marked spares and store it for possible future use. Then buy a decent working camcorder on ebay for not a lot of moneyI love repairing kit just for the challenge it presents...it keeps my brain amused and reasonably agile. I often buy faulty kit on ebay just so that I can repair it and learn from the experience. Some faults are unbelievably simple which is good in some ways but little challenge = no fun.There is always the exception though... I bought an EEV/Marconi thermal camera the other day for GBP65 in the hope that I could repair it. E2V (nee EEV) kindly supplied the service manual. After 15 minutes testing I found a shorted Tantalum capacitor ib the main 8.7V supply rail of the camera. Once the camera was fitted with a new capacitor the camera showed some signs of life but was not working correctly. I ran it on an external power supply and it worked perfectly. The cause of the problem was a 0.2 Ohm resistor that had climbed to 1.5 Ohms. It was the current monitoring resistor in the PSU and it had not taken kindly to a prolonged short circut on the camera supply rail. The PSU was in current foldback at around 100mA and starving the camera of correct power as a result. So Cause and Effect once again applies. After fitting 50p worth of components I have a superb little thermal imaging camera plus knowledge of how it works and the service manual to aid any future repair. A happy ending.The other side of the coin is a Ferguson Stereo VCR that I bought as faulty in 1988. At the time such stereo VCR were expensive and I thought I had a bargain at GBP50. What I didn't know at the time of purchase was that the VCR was damaged by a near misslightning strike. The owner told me some weeks later in casual conversation as his fridge, freezer and many other appliances had been destroyed ! Long story cut short, I bought the service manual whilst blissfully unaware of the lightning strike and spent over GBP100 in parts getting the VCR working. Most of the microprocessors and VLSI in the Mechacon were toast. I did learn a great deal about VCRs during the repair as the Ferguson service manual for that unit is said to be the best ever written, and was used on many VCR repair training courses. It was very detailed in terms of circuit operation and diagnostics. Not like todays service manuals that often just take you to board replacement level. The VCR ended up being a prop in 2001-2006 when I trained officers in some specialist electronics work.... I rigged it with all manner of nasties ! Its probably still used today. It never recouped its parts cost though, and I bought a better VCR whilst repairing it anyway ! The knowledge gained during repair had value though.Best WishesFraser

author: GabYoung92
author_rank: Regular Contributor
timestamp: November 07, 2012, 12:27:19 pm
content: Aurora,Thanks for your reply. I did question at first why that diode failed, to be honest, I'm not too sure. Playing with the unit, I feel that no further damage has occurred, I may be wrong though!I have ordered some converter boards (ZIF -> CF and ZIF -> IDE) to test the HDD, and if faulty replace with a CF card on the converter board.I have visually inspected most of the easily accessible boards using a microscope (including the HDD board) and there seems to be no physical signs of damage (That I could see). With the drive plugged in, there is 3.012V measured on the HDD, so the HDD is receiving power, just not booting. It is rated for 3.3V, seems a little bit low for my liking.It's mainly for fun and to learn from. So fat, $6 has been spent on the boards (eBay, China), and maybe a bit more on a CF card. Just come to think of it, I have 2 spare cards from my SLR camera.

author: GabYoung92
author_rank: Regular Contributor
timestamp: November 07, 2012, 12:28:32 pm
content: Forgot to add, good work on that camera!