Re: identical G05-802 problem with 2 different deflection PCBs

Yes, all checked and at the right places (several times even, as
powering up blows them :) ).

Last night, I started going through everything looking for dead
shorts, no luck at the moment but there's a lot left. After taking the
power brick out to check below the case, I did notice the transformer
is a replacement and has been spliced in. Initial comparison with the
wiring diagrams seem to indicate it's all done correctly but I'm going
to give it a lengthier check tonight.

Colin

On 01 Dec 2009, at 02:12, teeray wrote:

> Check for wrong Transistors or transistors in the wrong socket.
>
> Did you check to make sure
> Q708 = 2N3716 - NPN
> Q709 = 2N3792 - PNP
> Don't forget to check for collector-->emitter shorts
>
> Also check R720 and R721
>
> Tim
>
> -----Original Message-----
>> From: Colin O'Brien <colin@onepointzero.com>
>> Sent: Nov 30, 2009 2:28 PM
>> To: vectorlist@vectorlist.org
>> Subject: Re: VECTOR: identical G05-802 problem with 2 different
>> deflection PCBs
>>
>>
>> Yes, I checked the chassis. Even at multiple stages, with and without
>> the screws etc.
>>
>> Colin
>>
>>
>>
>> On 30 Nov 2009, at 14:09, COLIN DAVIES wrote:
>>
>>> I know you said you checked for shorts on the looms.... but I saw no
>>> mention of the chassis... So....
>>> Are any of the Chassis Transistors (body or leads) shorted to the
>>> chassis iself ?... ( The Screws should be insulated and you need to
>>> use a mica insualtor if it were misssing... That would be sure to
>>> cause trouble....
>>>
>>> Regards, Colin Davies
>>>
>>>
>>> --- On Mon, 30/11/09, Colin O'Brien <colin@onepointzero.com> wrote:
>>>
>>> From: Colin O'Brien <colin@onepointzero.com>
>>> Subject: Re: VECTOR: identical G05-802 problem with 2 different
>>> deflection PCBs
>>> To: vectorlist@vectorlist.org
>>> Date: Monday, 30 November, 2009, 11:42
>>>
>>>
>>> I did in the beginning, but since then I've only re-metered the
>>> sections that connect directly to the deflection PCB side without
>>> finding anything.
>>> I'll give it another thorough going through just to be sure.
>>>
>>> Colin
>>>
>>>
>>>
>>> On 30 Nov 2009, at 11:06, Pinx wrote:
>>>
>>>> Have you meter'd all your looms for dead shorts ?
>>>>
>>>> Pinx
>>>> ----- Original Message ----- From: "Colin O'Brien" <colin@onepointzero.com
>>>>
>>>> To: <vectorlist@vectorlist.org>
>>>> Sent: Sunday, November 29, 2009 11:18 PM
>>>> Subject: VECTOR: identical G05-802 problem with 2 different
>>> deflection PCBs
>>>>
>>>>
>>>>>
>>>>> Hello,
>>>>>
>>>>> I've been a lurker here for a while, quietly absorbing the
>>> insight but I've hit a problem that has me (and my limited
>>> knowledge) baffled.
>>>>>
>>>>> I have a working asteroids game board (2 actually), with which I
>>> can play fine on the scope (also when grabbing the signal from
>>> P100 instead of the test points)
>>>>>
>>>>> When I initially got the machine, I had problems with the monitor
>>> (G05-802) having no horizontal deflection and the spot killer being
>>> active. After checking the PCB, I replaced a couple of transistors
>>> on the board a well as the Q708 & 709 chassis transistors.
>>>>>
>>>>> Upon powering up, I would lose the 2 chassis transistors in
>>> question and sometimes the F700 fuse. I practically inspected every
>>> single component on the board, but found no extra faults. I looked
>>> for shorts, tested voltages (95V at P500, 30-35 VAC coming in at
>>> P100 pins 7 & 10, 12kV for HV etc) but found nothing that looked
>>> suspicious to me.
>>>>>
>>>>> I recently got a new known working/tested deflection PCB as a
>>> comparison/reference point, hoping that would help me see what was
>>> wrong or, at the worst, serve as a working board. Well, no luck
>>> there, when I plugged it in the spot killer was on and I had no
>>> horizontal deflection. I guess I can deduce from this that my
>>> problem is outside the PCB itself?
>>>>>
>>>>> Powering it up a second time to take some readings, the spot
>>> killer was still on but I'd lost the picture, turning brightness/
>>> contrast up only produced a faint haze towards the top of the
>>> screen.
>>>>>
>>>>> Inspection of the PCB revealed R713 was burnt to a crisp as well
>>> as its neighbours Q705 and Q706 both being shorted. I checked the
>>> chassis transistors, they were fine, I looked for shorts in the
>>> sockets, plugs and cables leading to them but found nothing wrong
>>> either.
>>>>>
>>>>> I replaced the dead components but powering it up now blows F700
>>> when I'm lucky or the chassis transistors. I'm weary of powering it
>>> up again as I don't feel like destroying components for the fun of
>>> it.
>>>>>
>>>>> I'm at a loss now, not sure where to look outside the PCB. Could
>>> the yoke be at fault? I'm in unknown territory here and would
>>> appreciate any pointers I can get.
>>>>>
>>>>> Thanks!
>>>>> Colin
>>>>>
>>>>>
>>>>>
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>>>>
>>>>
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Received on Tue Dec 1 03:46:33 2009