Re: Tempest - WG6100 Deflection board issues

Yep... The LV2000 Kit sorted the issue out... Was quite pleasantly suprised as I thought there would be more to the fault than that....

Now... my dilema.... I have two delfection boards.... One is the old one, and the other is the newer one with the imput protection built in..(that was in the starwars) - Both have the LV2000 mod..

I'm thinking it would be a good idea to fit the newer board in the Tempest as it hammers the monitor, and fit the older one in the Starwars... Does that sound sensible ?

I'll probably do the back to back zenner mod to the starwars for now... and upgrade the components when/if they fail in the future...

Cheers, Colin

  ----- Original Message -----
  From: John Robertson
  To: vectorlist@vectorlist.org
  Sent: Monday, September 22, 2008 4:41 AM
  Subject: Re: VECTOR: Tempest - WG6100 Deflection board issues

  Colin Davies wrote:
    Hi Guys,

    I've isolated the fault to either the yoke or the deflection pcb itself (I've not got a yoke or spare deflection handy to try substituting in a hurry) ... The chassis was quite happy to run without the HV unit powered up, so its safe to test (imho) without doing any damage.

    The -27v rail is fluctuating between -27v and 0v on the scope. (very odd !!) the +27V is fine... I can clip the scope on xy mode onto the yoke feedback resistors, and see the same fault that was on the monitor.

  Get an LV2000 kit to replace the original regulator section, your monitor wil be much more reliable AND you will probably fix this problem at the same time. I install the LV2000 kit in every W.G. Colour XY that comes through our shop. Reduces call-backs!

    Has anyone seen a shorted yoke on one of these before ? I'm hoping that its just something shorting out/breaking down on the deflection pcb - maybe someone has installed a capacitor the wrong way round or something ? It's certainly been worked on before.

  As you found out the yoke was not your problem. You CAN run XY (or raster) monitors with the yoke unplugged as a test. However NEVER attempt to run these monitors with any transistors unplugged - particularly the output transistors! That can or will destroy other transistors or resistors.

  Have you resoldered ALL the Molex pins on the board that everything plugs into? Very common for one or more pins to have a cracked solder trace so it is intermittent.

  John :-#)#

    I'm reasonably certain that the chassis transistors are ok, as I swapped the plugs round, to swap the pairs for the regulator and one of the deflection pairs.

    As a further note... Q100 and Q101 had been replaced with standard 7824 / 7924 voltage regulators, they look like they have just been dropped in with no further modifications to the circuit... surely this is not good practice ?? I thought this might be the problem, soI dropped in some transistors to replace - a mpsa06 and an BD238 with the legs swapped over (not got a mpsa56 to hand).

    I'll get these, just need a little more time to investigate.

    Cheers, Colin

      I plugged in the monitor for the first time ( this was aquired a few months ago and it had a known fault) and getting a display... BUT something is breaking down in the chassis, and its sucking some of the vectors up into the middle of the screen !! (Looks fine on the XY scope !!)

      I'm thinking I have a HV board fault... I can hear what sounds like HV tracking (not the deflection chatter) - I took this picture....

      http://www.jammaplus.co.uk/forum/uploads/ColinD/2008-09-20_203630_tp4.jpg

      I cant leave it on for long as the phosphor will burn... I think I'll try another HV unit... and if not.. start trouble shooting the deflection with the brighness turned down too when testing !!

      Any ideas please ?

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