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Vintage Television and Video Vintage television and video equipment, programmes, VCRs etc. |
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24th Nov 2021, 4:00 pm | #21 |
Triode
Join Date: Nov 2021
Location: Folkestone, Kent, UK.
Posts: 16
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Re: Panasonic DMR-E75V dead
Thank you. You are correct in the need for caution. I have very limited experience - call me a complete beginner - i have a simple multimeter with some experience of its usage.
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24th Nov 2021, 4:30 pm | #22 |
Octode
Join Date: Sep 2020
Location: Thetford, Norfolk, UK.
Posts: 1,741
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Re: Panasonic DMR-E75V dead
OK, have you got the service manual / schematic for your unit. The next stage is going to be powering it up while exposed - CAUTION - and measuring the voltages coming from the power supply.
I would suspect that the power supply is probably not running and not therefore outputting any voltages. There maybe people here on the forum who would take a look at just the power supply for you if you are not comfortable working on live equipment. |
24th Nov 2021, 4:59 pm | #23 |
Triode
Join Date: Nov 2021
Location: Folkestone, Kent, UK.
Posts: 16
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Re: Panasonic DMR-E75V dead
Thank you agardiner et al. I think you are correct in that there is no power output at all. I think before i start working on any live equipment, i will replace the output IC as i mentioned in a previous post. I can get one with the same reference number online and at least i am then cutting down the possibilities! i have seen some people undertaking testing and measurement but i dont have any circuit diagrams etc
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24th Nov 2021, 5:26 pm | #24 |
Octode
Join Date: Jan 2003
Location: Ashby-de-la-Zouch (it's not by the sea)
Posts: 1,255
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Re: Panasonic DMR-E75V dead
I don't know whether this is for the DMR-E75V or not. It's labelled as being the PSU for the DMR-EX75V. Is this one in the same device perhaps?
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24th Nov 2021, 5:29 pm | #25 |
Octode
Join Date: Jan 2003
Location: Ashby-de-la-Zouch (it's not by the sea)
Posts: 1,255
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Re: Panasonic DMR-E75V dead
Oh perhaps it's not. The DMR-E75V (no 'x') does look like a different machine externally. Sorry if I've introduced a red herring!
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Now where on earth did I remove that from? |
24th Nov 2021, 5:31 pm | #26 |
Octode
Join Date: Sep 2020
Location: Thetford, Norfolk, UK.
Posts: 1,741
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Re: Panasonic DMR-E75V dead
Most of these types of supply have a high value resistor, (typically 1M) to 'start' the supply. Basically they provide power for the switching IC before it starts to oscillate, whereupon it usually gets its power from a secondary winding on the main transformer. These high value resistors frequently go open, particularly as the associated small electrolytic goes high ESR. So worth checking these resistors in the primary.
When the switching IC fails, it is usually fairly obvious, as they generally fail short circuit, so blowing fuses etc. |
25th Nov 2021, 2:23 pm | #27 |
Dekatron
Join Date: Apr 2005
Location: North Wales, UK.
Posts: 6,921
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Re: Panasonic DMR-E75V dead
If the resistor has gone open circuit the main electrolytic will hold its charge and be ready to bite you! Check it with your meter.
As a very rough rule of thumb, I find if the board's been disconnected from the mains for a short while, a high voltage on the main smoother means the PSU isn't doing anything (the start-up resistor/capacitor or the switching IC at fault), a small voltage points to a secondary fault and absolutely nothing points to rectified mains not getting to the circuit. |
25th Nov 2021, 3:37 pm | #28 |
Triode
Join Date: Nov 2021
Location: Folkestone, Kent, UK.
Posts: 16
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Re: Panasonic DMR-E75V dead
Thank you all. I have had a good look at the power side this morning and cannot find anything labelled as a resistor - or that looks like one. Plenty of capacitors, inductors, diodes, the IC but only two very small pink resistors elsewhere on the board ie not close to the power side
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12th Dec 2021, 3:50 pm | #29 |
Triode
Join Date: Nov 2021
Location: Folkestone, Kent, UK.
Posts: 16
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Re: Panasonic DMR-E75V dead
Thank you for all your help.
I have changed the IC on the power side and now i actually have some power and a display!!! However, it comes up with a U99 error and there does not seem to be anything happening on the DVD recorder side. Any advice? |
12th Dec 2021, 4:43 pm | #30 |
Heptode
Join Date: Mar 2015
Location: Lefkada, Greece
Posts: 969
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Re: Panasonic DMR-E75V dead
According to the service manual, the U99 error code is displayed when a communication error has occurred between the main microprocessor and the timer microprocessor.
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13th Dec 2021, 11:02 am | #31 |
Dekatron
Join Date: Apr 2005
Location: North Wales, UK.
Posts: 6,921
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Re: Panasonic DMR-E75V dead
U99 is not a good error code, and tends to be a fault on the MPEG board which interfaces with the DVD or, as Fivos says, a general communication error.
Try several hard resets and double check you haven't disturbed any wiring (weve all done it!). Now you've reminded me to get back to that EZ48 with U99 on the display - thanks!!! |
14th Dec 2021, 5:03 pm | #32 |
Triode
Join Date: Nov 2021
Location: Folkestone, Kent, UK.
Posts: 16
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Re: Panasonic DMR-E75V dead
I think I have the problem. I replaced the ribbon cable from the DVD to its processor because the original was damaged. I have now noticed that the replacement is not the same. On the original, I think it is the first line crosses over and joins somewhere about the third line (on both edges and at each end). I cant seem to find any replacements that match this configuration so I think I am well and truly thwarted unless anyone has any suggestions. I have learned a lot from you chaps though so not all wasted time.
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14th Dec 2021, 5:54 pm | #33 |
Dekatron
Join Date: Apr 2005
Location: North Wales, UK.
Posts: 6,921
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Re: Panasonic DMR-E75V dead
Can you post a picture? I have quite a few scrap EZ seies machines and might have the cable you need.
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15th Dec 2021, 11:26 am | #34 |
Triode
Join Date: Nov 2021
Location: Folkestone, Kent, UK.
Posts: 16
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Re: Panasonic DMR-E75V dead
Picture attached. The cable is like this at both ends and is about 29cms long
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15th Dec 2021, 1:48 pm | #35 |
Hexode
Join Date: Dec 2012
Location: Worcester, Worcs, UK.
Posts: 257
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Re: Panasonic DMR-E75V dead
This sounds very similar to what's going on with my machine
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15th Dec 2021, 6:20 pm | #36 |
Dekatron
Join Date: Apr 2005
Location: North Wales, UK.
Posts: 6,921
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Re: Panasonic DMR-E75V dead
Any chance of the width? It's critical obviously and you'd be surprised how many close variations there are. Also is it a straight piece or is there a bend in it?
PS That crossover is bizarre. I'll look tomorrow and see what I have. |
15th Dec 2021, 10:04 pm | #37 |
Moderator
Join Date: Feb 2006
Location: Wembley, Middlesex
Posts: 7,224
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Re: Panasonic DMR-E75V dead
You can post his details on here, phone number / Website.
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16th Dec 2021, 11:57 am | #38 |
Triode
Join Date: Nov 2021
Location: Folkestone, Kent, UK.
Posts: 16
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Re: Panasonic DMR-E75V dead
The cable is 13/16th of an inch or 21mm wide. It has three right-angled bends in it to enable it to go from the left hand side of the recorder (as you face the tray front), under the recorder and then turn to 90 degrees to enter the top of the micro-processor!
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16th Dec 2021, 1:40 pm | #39 |
Triode
Join Date: Nov 2021
Location: Folkestone, Kent, UK.
Posts: 16
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Re: Panasonic DMR-E75V dead
This machine records onto DVD-RAM and DVD-R. It strikes me that other Panasonic models that do the same eg DMR E55 might have a similar type of cable/microprocessor
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16th Dec 2021, 1:54 pm | #40 |
Dekatron
Join Date: Apr 2005
Location: North Wales, UK.
Posts: 6,921
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Re: Panasonic DMR-E75V dead
The one I have is 22.5 mm wide and only has one bend. Crucially it doesn't have that weird corossover in your picture.
I'll keep looking. |