Author Topic: Operation Fixit! (Read 5366 times)

marshall · « **on:** December 17, 2009, 01:30:21 pm »

Hi all, new to this forum and cant seem to find the answer to my question, so apologies if its already been asked.
I have an arcade machine called 'operation thunderbolt' which has been working perfectly since I bought it in June, its kept in my garage and since the weather has changed, its a very cold garage.
Anyway I decided to switch the machine on to let it warm through incase it gets damp when I became aware that the monitor isnt displaying colors correctly. I left it on overnight with no improvement. The screen was very red, but now it seems more purple/blue. Ive adjusted the gain screws on the monitor board with no improvement. According to the manual its a Hantarex 9000 monitor.
So can anyone give me advice as to whats wrong?
Is it likely to be because its cold or more serious? Im in the UK so its a 240 volt with a transformer.

Thanks

grantspain · « **Reply #1 on:** December 17, 2009, 01:43:59 pm »

sounds like the degauss is not working,do the colours shift if you rotate the machine

marshall · « **Reply #2 on:** December 17, 2009, 01:54:21 pm »

Thanks for the reply.
No nothing changes when the unit is moved, the screen is very blue/purple.

grantspain · « **Reply #3 on:** December 17, 2009, 02:00:03 pm »

got a photo?
sounds like the red drive transistor shorted and blew

marshall · « **Reply #4 on:** December 17, 2009, 02:14:53 pm »

There is some discoloration down the side and bottom of the screen where its gone slightly yellow.

grantspain · « **Reply #5 on:** December 17, 2009, 02:23:08 pm »

looks like the red drive transistor is short circuit

marshall · « **Reply #6 on:** December 17, 2009, 02:27:30 pm »

That doesnt sound good.

Is it likely to be because its damp/get better when its warmer, and easy to repair?
I can handle a soldering iron but do you know which transistor and the value?
I have the schematics but have no idea which one it is.

grantspain · « **Reply #7 on:** December 17, 2009, 02:39:21 pm »

http://wiki.arcadeotaku.com/index.php/Hantarex_Polo_1

marshall · « **Reply #8 on:** December 18, 2009, 03:57:57 am »

OK thanks for your help, I will change them and see what happens.

grantspain · « **Reply #9 on:** December 18, 2009, 04:17:23 am »

remove T2 and T3 ,that will prove the fault

marshall · « **Reply #10 on:** December 18, 2009, 09:50:22 am »

Im a total novice with this, what should happen if I remove those transistors?

Im assuming that if they are faulty, there should be no difference in the picture?

grantspain · « **Reply #11 on:** December 18, 2009, 09:58:11 am »

nah,if you remove the red drive transistor then you should lose all red,if the screen remains red the crt red gun is short

marshall · « **Reply #12 on:** December 18, 2009, 10:04:10 am »

Sorry, Im confused. I thought red had gone and replacing their transistors would restore it, the screen is very blue/purple.

grantspain · « **Reply #13 on:** December 18, 2009, 10:56:51 am »

looks red to me from the photo

marshall · « **Reply #14 on:** December 18, 2009, 01:38:52 pm »

I dont think the photo looks the same as it does when Im looking at the actual screen, but I think you know more than me so will just do as you said and change the transistors. I can change the red and if that doesnt work, change the others. What was it you said if that doesnt work, its the tube?

grantspain · « **Reply #15 on:** December 18, 2009, 01:43:25 pm »

i don't have the manual handy at the moment but the drive transistors are the ones with the heat sinc fins attached,they are a common fault on hantarex
you could swap them around and see if the colour problem changes
worst case scenario is crt,its unlikely but you can't rule it out

marshall · « **Reply #16 on:** December 18, 2009, 02:10:37 pm »

Im so glad I found this forum

The transistors are £2 for 10 from ebay, cheaper from online dealers. Either way at this time of year its going to be a few weeks before I get the replacements. If I get 10 then they can all be changed anyway.

Could it be the cold and damp thats caused this problem?

grantspain · « **Reply #17 on:** December 18, 2009, 02:45:23 pm »

damp can be a dangerous thing with crt,more than likely i expect yours is just suffering from a one transistor faulty but if you have ever seen a damp crt arc then you would never put a cab inside a garage/shed
the transistor i think is a BF41?

marshall · « **Reply #18 on:** December 18, 2009, 03:18:59 pm »

Believe me if I could have it in the house I would, I have a motorcycle in there too which would also be in the house if the wife would let me, it used to be until we got married.
I have the schematic and it says the transistor is a bc548b and the others are bc558b. Is that not the correct ones then?

grantspain · « **Reply #19 on:** December 18, 2009, 04:00:19 pm »

T2 BF859

marshall · « **Reply #20 on:** December 24, 2009, 08:56:15 am »

Is it the transistors off this board which need replacing?

grantspain · « **Reply #21 on:** December 24, 2009, 09:24:04 am »

sorry mate i gave you the wrong transistor ,for some reason i thought you had said a polo monitor and in fact you have a 9000-forgive me
the transistors you should be looking at are tr7,tr8,tr9 on the main chassis and tr201 on the neck card
the bf859 will replace bf459 just fine-just looks different

grantspain · « **Reply #22 on:** December 26, 2009, 05:42:12 pm »

i remember there is something else that can cause your problem,do you have a contrast pot on the chassis or is it a 3 way switch?

Nipedley · « **Reply #23 on:** December 27, 2009, 03:58:41 pm »

I had the same issue with the blue transistor on one of my MTC9000 chassis, it is indeed a BF459/859 (the 859 has a nice big heat sink

)

Mine were all on the neckboard I do believe (the board in your picture).

marshall · « **Reply #24 on:** January 07, 2010, 05:21:02 am »

Sorry I havent been back, Ive been busy with xmas etc.
Anyway due to the weather Im hoping to sort this in the next couple of days.
Grantspain I think its a pot but cant be sure, I think Ill take some more pics and let you decide.
Nipedley, you board is like mine? So the transistors which need changing are on this board? Im a complete novice but can handle the soldering iron, Im totally not sure which to change now. The board for the monitor is at the back of the cabinet behind the monitor chassis and looks like a real pig to get at, so Ill be dead chuffed if its the little board in the picture that need the repair.

grantspain · « **Reply #25 on:** January 07, 2010, 10:56:30 am »

could be a pot,the best advice i can give is to swap pot and transistor with another colour

marshall · « **Reply #26 on:** January 10, 2010, 04:44:01 am »

Im going to update this now as I go.

Just put it into service mode and this was the result.............

So it looks like no red?

Im off now to swap around the 459s..........

marshall · « **Reply #27 on:** January 10, 2010, 05:39:00 am »

Ive taken out the first transistor and this was the result,,,,,,,,,,,

marshall · « **Reply #28 on:** January 10, 2010, 05:41:11 am »

Then there was a crackle as I touched the second transisror (the one in the middle of the last pic) so I put it back together and got this.......

marshall · « **Reply #29 on:** January 10, 2010, 05:42:30 am »

So I removed the one which crackled (one in middle of pic) and got this............

marshall · « **Reply #30 on:** January 10, 2010, 05:45:17 am »

Theres clearly a picture being generated, but Im unsure why the screen went that red??

Is the advice still to remove the third transistor and swap them around, or should I just buy new ones and replace them all, do you still think its the transistors which are causing the fault??

grantspain · « **Reply #31 on:** January 10, 2010, 05:48:56 am »

can you take a photo of your main monitor board as well.
imo change the red drive transistor and check for bad solder joints

marshall · « **Reply #32 on:** January 10, 2010, 06:01:38 am »

Just pricing them up from fleabay as maplin dont list them.

grantspain · « **Reply #33 on:** January 10, 2010, 06:13:44 am »

on the first photo you can see a large blue pot on the bottom left,adjust that to see what affect it makes

marshall · « **Reply #34 on:** January 10, 2010, 06:27:15 am »

Ive removed 201 and 203 from the neck card, should I try it with those removed?
Also what is the transistor value needed for the main monitor board?

Ive sourced the bf459 and according to the schematic its tr7 bc558b tr8 bc548b and tr9 bc548b is that correct??

grantspain · « **Reply #35 on:** January 10, 2010, 07:03:31 am »

just go with the neck transistors for the moment,imo you should put those transistors back in and check
at the moment you seem to be missing gain rather than colour-those pots on the neck card can cause grief so its worth giving them all a tweek

marshall · « **Reply #36 on:** January 10, 2010, 08:59:01 am »

Ok just got replacement bf459 so going back to put them in now, the pot you spoke of made the screen brighter/darker. I didnt get replacement pots but have twiddled all of them on the neck card when I first got this problem and seem to remember one of them having little effect.
Will report back when these are back in.

marshall · « **Reply #37 on:** January 10, 2010, 09:36:01 am »

First picture is with red transistor missing, second picture is with red and third is with all three transistors replaced with new ones, and I can confirm the pots next to each colour all have an effect on the picture, the red is definatly working. The blue pot on the mainboard makes the picture brighter/darker. As you can see the problem still exists.

marshall · « **Reply #38 on:** January 10, 2010, 11:13:59 am »

Ive had a develpoment, I confess to having adjusted the brightness on the the HT transformer and was looking at the picture when there was a sizzling noise and the whole thing went off. I unplugged the unit then plugged it back in to be greeted by a new problem in so much as the sides of the picture have dissapeared!!!
Now what?

Have I done more damage???

grantspain · « **Reply #39 on:** January 10, 2010, 12:19:39 pm »

the flyback transformer could be on its way out,a monitor of this age could have a number of problems,i reckon you are in the u.k-whereabouts are you?


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