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Hitachi 42PMA400E fan modification

Discussion in 'Plasma TVs' started by Darren Blake, Nov 21, 2003.

  1. Darren Blake

    Darren Blake
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    Guys and gals.

    I was going to add this to the end of one of the bazillion "my PMA has a noisy fan" threads, but since I could not find the best one to append it to, I thought I'd start another. :D

    If this subject interests you, you may recall that I was getting a positive response from Hitachi UK regarding an official modification for the single-fan (later) version of the PMA screen. Then I went all quiet.

    To cut a long story short, there is now an officially endorsed modification to the fan which should go a long way to making the screen truly quiet. The reason I have not posted anything up until now is that a) the research at Hitachi in Japan took a lot longer than my UK contact thought it would, and b) I was specifically asked by Hitachi UK to keep it under my hat until details of the modification were officially released. Since they were being so helpful, I saw no reason not to comply with their wishes.

    Anyway. Today I got a telephone call from someone at Hitachi who is arranging to come out to my house to perform the modification. He will be visiting my house in person to support a local television engineer (to whom Hitachi would have normally just sub contracted the job).

    At this stage I would ask that anyone interested in this modification does not contact Hitachi, but instead waits to see what happens when I have my screen worked on, which should be sometime between 1/12/03 and 5/12/03.

    Cheers!
     
  2. ASH1

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    Hi Darren, did they confirm that the later displays have had this mod done already, and if so from what date or serial No. I can't hear any noise from mine but that doesn't mean it won't start if the future, please keep us up to date.
    ASH1 :smashin:
     
  3. Darren Blake

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    Hi Ash.

    When I started to see posts referring to silent PMAs I did ask my guy at Hitachi whether new screens had been pre-modded. Come to think of it he never actually gave me a direct answer, but it seems logical.

    I shall try to remember to make a point of asking their engineer when he calls.

    Regards,
     
  4. wbessada

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    Great news Darren, it'll be great to hear what the mod involves.

    I haven't found my PMA to be too noisey but I can hear it when I specifically listen for it - so if there's a free mod to make it silent then wooohooo!

    I was concerned to hear the early posts that the mod might disable the fan(s) as this may well have an adverse effect on the life of the display or electronics.

    But great to hear they're actually doing something about it!

    :clap:
     
  5. ASH1

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    Hi Darren, if you think of it can you please ask from what date or serial number the mod started from (if there was one).

    ASH1 :smashin:
     
  6. sdemmery

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    Well done Darren for following this up. Im with Ash1 on this, I dont here the fan on my new 400. :D Which makes me also think that the mod may already be done. So I to would e interested if this is true.

    Cheers

    Stuart
     
  7. Darren Blake

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    I'll make a note to ask the question about pre-modded screens.

    From what I undertand of the mod, it invloves reducing the voltage to the fan in the single fan models. The guy from Hitachi who called me the other day said this was pretty much just a case of taking the back off the screen and changing the fan power supply from one socket to another. This kind of suggests to me that they either have some kind of standard multi-speed fan module which is used across many screens, or they thought noise may be an issue from the start.

    I'll be watching them do it, so I'll give more details after the job is done.

    As for the life of the screen, I gather that the main reason for the delay in this mod coming out was due to research into the affect on lifespan back in Japan. Since it is an official mod that does not void warranty, I can only assume that there should be no adverse affects. I certainly hope not anyway! :D
     
  8. ASH1

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    Hi Darren, from what I was told by Hitachi tech support in the past is that no 400E has only one fan. I've been told that one fan can be disabled to reduce fan noise but he didn't recommend it. He told me all 400E had two fans.
    ASH1
     
  9. Darren Blake

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    Ash, your contact seems to be misinformed. Did you go through the normal "customer" tech support? I have been talking to the guys in direct contact with Japan.

    The first PMAs had two fans and could be mounted in either portrait or landscape orientation.

    Later screens had one fan removed. These screens can only be mounted in landscape orientation. My screen has an orange addendum sheet in the instruction manual stating this limitation (although it doesn't state why).

    Finally, there is now speculation that the latest screens have a single fan operating on a reduced voltage, or maybe no fans at all.
     
  10. ASH1

    ASH1
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    Hi Darren, I also have the orange sheet and as you say it's only speculation on the one fan, it would be nice to know for sure. The people I have been speaking to are on this number 01628 643349 is this the same number as yours?

    ASH1
     
  11. Blu-rayx

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    :hiya:


    My 400pma only has one fan!


    DVD :)
     
  12. Darren Blake

    Darren Blake
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    The speculation is on the newest screens having a single fan operating on reduced voltage, or possibly even not having any fans at all.

    I have been talking to Hitachi UK's Technical Sales Manager by e-mail. No idea what his telephone number is. The guy who telephoned my last week is from another department and he also mentioned that only early screens have two fans.
     
  13. Darren Blake

    Darren Blake
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    The appointment has been set for 2pm on Monday 1st December. :D
     
  14. ASH1

    ASH1
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    I'll look forward to your news with interest.
    ASH1
     
  15. Darren Blake

    Darren Blake
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    Right-ho. I had my screen "done" today by a local TV repair shop with a guy from Hitachi UK present. Firstly, I can't praise these guys enough for service. I was actually 15 minutes late for my own appointment (got held up after dropping my car in for a service). They were actually waiting in my driveway for me when I finally arrived, rather than just buggering off.

    Firstly, to answer some questions:

    1) To the best of the Hitachi guy's knowledge, there are NO PMAs that come with this modification straight from the factory, so he could not give a serial number for the changover. The PMA is still considered by Hitachi to be an "industrial" screen, although they recognise that many people use them for the home. For this reason, the modification is only being offered in a case by case basis for people who have a problem with noise from the fan(s).

    2) There are PMAs from the factory with both one fan and two fans. This modification is simpler if the screen only has one fan, but can also be done on screens with two fans.

    Here's how the mod works (this information is in the public domain now, so hopefully I won't upset anyone if I post it here).

    If you look at the rear of the screen, through the air vents in the back, near the top in the centre you should be able to see a the top fan (the only fan in single-fan models) on a brown coloured circuit board. To the right of this, you should see a white plug with a red, white and black wire going into it. The identification for this plug is written on the circuit board and is "CN304". This plug is the power supply for the single fan. According to Hitachi it is a thermostatically controlled supply which switches between high and low voltages to control the fan's speed according to the screen's temperature.

    Now look at the bottom right of the back of the screen. Again, through some air vents, you should be able to see a similar plug on a green circuit board, labelled "PFAN1". The plug is just below a bundle of white wires. This is the power supply for the second fan in the earlier, two-fan models. It is (again according to Hitachi) a constant low voltage supply.

    On the two fan models I assume you will see a wire coming from this plug. However, on the single fan models you should see a "dummy" plug with a brown wire linking pins 2 and 3 together.

    Basically, what the modification does is swap the supply for the single fan over from the thermostatically controlled high/low plug CN304 to the constant speed PFAN1 so the fan always runs slower and more quietly. The dummy plug is still required and gets swapped from PFAN1 to CN304. The lead on the fan is just long enough to reach the PFAN1 plug, and you can clip it along the bundle of white wires mentioned above.

    This procedure is so simple that you could potentially do it yourself. I can, of course, accept no responsibilty for the results if you do. However, why bother when you can get someone to come out and do it for you?

    The best approach would be to contact your local authorised Hitachi dealership, who should have access to the details. I'd appreciate it if you didn't bombard them with my name! :)

    The modded screen is not totally silent, and it may be my imagination, but I think I can hear a PSU style buzzing that was not there before. Probably me being paranoid, but it could be the rerouted wire vibrating against something, or a side effect of using the other power supply for the fan. I'll live with it and see how it goes.

    Hope this helps!! If I get time tomorrow I will draw a diagram to go with this description.
     
  16. sdemmery

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    Nice one Darren, glad you got it sorted. I too hear a buzz from the PSU, but as Ive said before never any noise from the Fan or Fans!

    It's a refreshing to hear of some decent customer service for a change. Well done Hitachi!

    Stuart
     
  17. ASH1

    ASH1
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    Hi Darren, thanks for the info and a diagram would be great. As yet I have no need for any service as my screen is silent, but could you please give me the name of your contact at Hitachi. If I should need this done in the future I don't want to be told that they don't know what I'm on about. Every time I talk to Hitachi they keep insisting that all 400e have two fans, and as we all now know this is not the case. It would appear only a few people at Hitachi know what's going on.

    ASH1:smashin:
     
  18. paulS

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    Firstly a thanks to Darren for the info.

    I purchased my 400e in March this year (single fan version).
    It is nearly out of warranty – so I decided to do the mod myself.

    Easier than I thought (after getting it down off the wall !!!!),
    Exactly as Darren explained and if I have problems during the last couple of months of warranty - there was no seal to break - so it’s easy to return to its original state.

    Fan noise is still just about noticeable (with no audio) - but a still a big improvement.

    To help a little see attached photo, Red arrow points to old position “CN304" (note the fan cable coiled up above it), and the Blue arrow marks the new plug position "PFAN1".
    Cable is just about long enough to get to the new position, but by a very direct route.

    paul.:smashin:`
     
  19. dblake

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    Hi Darren

    Thank you very much for your persistance with Hitachi.


    I've done the mod myself and it works like a dream. It doesn't reduce the noise altogether, but it certainly reduces it. Very easy to perform the mod.

    Many thanks again

    Dave
     
  20. Blu-rayx

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    HI,


    I did the mod 2 weeks ago,big improvement :smashin:

    My living room is quite big so now i can't hear it,even in quiet moments in a movie :D


    Thanks Darren :)


    DVD
     
  21. Paul97

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    Does this only apply to the 400e. I have the PD3000 model which has a "Buzzing" sound coming from the top rear vent.:confused:
     
  22. Deron

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    pd3000 model has no fan in the screen...

    It's in the media box.
     
  23. Paul97

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    Engineer says it's a transformer problem at the rear top vent area, and thinks he can fix it, could you please let me know why you know it's the media box as this might explain my lip sync problem while I watch Digital TV through a set top box (Nokia 221T).

    Cheers
    Paul:smashin:
     
  24. Deron

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    I don't know if it's the media box causing your lipsync, but the processor is in the media box and this is where the fan is located.

    As for the screen buzzing, this is a known 'feature' of this screen and after a search, this thread should be very useful to you.
     
  25. Paul97

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    Deron
    Thanks for your help, If I can't get this fixed my very understanding wife has said I can get a Denon 3803 amp to compensate for the audio delay, Sheeeeeeee's a good un. But I begrudge paying £100's for another amp when I am perfectly happy with my Yammy 630.

    Cheers

    Paul :hiya:
     
  26. john kelly

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    :clap: had my 42 inch plasma fan upgrade done and now it makes no sound, quite movies are not drowned out by the fan, at last the plasma i was looking for quite and supurb picture qualit.
    you have to moan at Hitachi to get them to do it but they will do it for free.
    make sure the Hitachi engineer fits a new fan at the same time.
     
  27. jaffakj

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    After reading this thread I am filled with hope!! I have one of the earliest 2 fan models, and watching TV is like listening to concorde take off, the fans are so noisy!

    Can this mod work with the 2 fan model - ie, can I just disconnect the bottom fan and modify the top one to use the PFAN output?

    Hope people are still reading this thread after all this time!

    Cheers
     
  28. paulS

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    Should work ok - just remember to short pins 2-3 on plug CN304.
    The single fan models had a dummy plug to do this.....

    Still using my PMA400 several years later with the mod.

    Cheers,

    Paul.
     
  29. laser

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    Please let us know how you get on.

    I have 42PMA400E which has given three years of sterling service but I'm not sure I have the confidence to tinker with the internals.

    I've just dicovered the wonderful world of high def on the 42PMA400E and stream 1080i content from a Sony HC1E camcorder via component to hte plasma. My god it does look impressive, even on a 3 year old plasma. Blows the pants of next doors 37inch Sony LCD, although I do have to turn the volume up a little to drown out that fan noise :D
     
  30. hat1

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    Sorry I'm a bit late to the party but i finally mustered up the confidence to try this mod and it worked great, thanks a lot to Darren for his notes.

    .... in fact it was that easy I was wondering if anyone had replaced the original fan with a quieter one (if so which one and where did you get it from ?) or disconected it altogether !?

    Don't get me wrong it's a lot quieter than it was, but like everything in life you always want more ! :D.......besides, i remember when TV's never made any noise apart from the speakers !
     

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