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Star Wars upright - restoration
shilmover:
Okay... Finally got a few minutes to check things over and noticed that HV2 (7924) was blown (as in to pieces :o)... I replaced both the 7924 and the 7824, plugged it all in and more sparks... When the smoke cleared, I checked and noticed that the new 7824 was blown. :banghead:
A couple of notes:
1. The 7824 was metal on metal... The 7924 was insulated.
2. When I removed the cap that connects to the monitor (can't remember what its called), I noticed that the wire was pushed out a bit and its end and the 2 ends of the clips were out too far.
Any idea what might cause this? Beyond this and a cap kit, any other recommended changes before I plug it all back in?
Level42:
Shil,
First try to get it running stable without the BU406D in place. Remove it completely and then fix the regulators. It's normal that one of the regulators is insulated and the other not, but I'm not sure which is which (as long as you did it the same as it was it should be OK) However MEASURE if there are no shorts on those etc. Did you check out the diodes that were added to the board (factory modification) and did you check the big resistors ?
If you get it to run stable without the BU406D, or if you didn't find anything else, you need to check the big diode that's going from the HVT.
Sorry I haven't got all the part numbers now....will follow up on that.
You do have BU406D's and NOT BU406 ?
About the clips: If they are too far out, you might (but not very likely) be shorting the 19.5 kV to the ground via the condictive cover of the CRT (pic?)...
Don't give up ! You'll fix it :) !
shilmover:
--- Quote from: Level42 on November 02, 2007, 02:38:58 am ---Shil,
First try to get it running stable without the BU406D in place. Remove it completely and then fix the regulators. It's normal that one of the regulators is insulated and the other not, but I'm not sure which is which (as long as you did it the same as it was it should be OK) However MEASURE if there are no shorts on those etc. Did you check out the diodes that were added to the board (factory modification) and did you check the big resistors ?
--- End quote ---
remember, I am still fairly new to this... I will try that... Where is the BU406D? I did not replace that... I did measure for shorts... there were none. I do not believe that the diodes where added. Can you send me a picture of what that looks like? I did not check the resistors (which ones, what should I check?)
--- Quote from: Level42 on November 02, 2007, 02:38:58 am ---If you get it to run stable without the BU406D, or if you didn't find anything else, you need to check the big diode that's going from the HVT.
--- End quote ---
ok
--- Quote from: Level42 on November 02, 2007, 02:38:58 am ---Sorry I haven't got all the part numbers now....will follow up on that.
--- End quote ---
Thanks!
--- Quote from: Level42 on November 02, 2007, 02:38:58 am ---You do have BU406D's and NOT BU406 ?
--- End quote ---
Yes. I have a couple.
--- Quote from: Level42 on November 02, 2007, 02:38:58 am ---About the clips: If they are too far out, you might (but not very likely) be shorting the 19.5 kV to the ground via the condictive cover of the CRT (pic?)...
--- End quote ---
I fixed it...
--- Quote from: Level42 on November 02, 2007, 02:38:58 am ---Don't give up ! You'll fix it :) !
--- End quote ---
I am so not giving up. Especially after seeing what the Amplifone looks like compared to the WG Monitor. ;D
Level42:
Hey Shil, I am aware of you being relatively new to this, you did an amazing job so far already IMHO :)
Sorry if I came to harsh, that was not my intention at all, just trying to help :) :cheers:
I just hope you didn't blow-up the new Cinelabs HTV ::)
My guidance in getting my Amplifone running again was the Amplifone FAQ document. Although there are some flaws in it (f.i. Q2 and Q3 are mentioned wrong way around) it _is_ a good guide. However, I have been educated in electronics and it is my work so maybe I'm just a little more experienced. Whatever :D
OK first thing: Remove the BU406D, wether it measures ok or not (since you have some spares, I'd replace it anyway)
So for now, de-solder the BU406D from the PCB and remove it from the cooling plate.
The added diodes I'm talking about should be on the solder side of the PCB. Here's a pic that shows them:
You can see one exactly on the burnt spot, the other is to the right of it on he wide track. You can check these for shorts.
If these diodes are not there, you probably don't have a "real" SW HV-PCB, but it was used on another game. You definitely must add the diodes if they are not there. Same goes for the really big resistors R20 and R21.
These resistors are also "modded in" at the factory, but they are on the component side. One of these resistor caused that burn spot on my PCB. Here's a pic that shows them:
They are the big black things near the left voltage regulator and the other near the cooling body. They should measure around 50 Ohms. Here's a close-up of the bad one on my PCB:
This first picture also shows that the left voltage regulator has the insulation. You can see the (top of the) thermal pad AND (VERY IMPORTANT) the insulator under the screw/bolt that's holding it. You could measure between the two screws on the regulators as one is electrically connected to the cooling body and the other not, so you should measure OPEN. If you measure a short, something's wrong with the insulation !!
Check again both voltage regulators on shorts. Sometimes you will have to de-solder (a leg of) a part to see what is causing the short. Sometimes parts are in parallel, so you can't tell which is shorting).
What color is your PCB ? If you have a blue one like me, the diode going from the HVTis near the HVT itself (I had to move it to the solder-side to allow the Cinelabs HVT to fit, as they point out in the installation instructions).
Here's a pic, but it's already moved there:
These are the main things to check. You should also check all the other diodes and transistors for shorts.
If all seems well, power up the board with the BU406D still _uninstalled_. Then you should check the output voltages of the regulators. They're not going to be exactly +24V and -24V. That is because of the resistors that are "bridging" these regulators partially. It should be around those values though....
If everything stays ok, reinstall the BU406D. NO insulation there, the metal back of the BU406D needs to make good contact with the cooling plate ! so turn the screw and nut pretty tight (not over-tight). I moved the screw to the outside to make this easier (nut on the inside).
Then hopefully you have already found the problem, and hopefully your HVT survived !
shilmover:
Thanks... You definitely did not come across as harsh... :)
The diodes are not there, but I will add them... I have a new Cinelabs HTV in there, so hopefully its still good...
I think my board is white... I did not move a diode (you stated " the diode going from the HVTis near the HVT itself (I had to move it to the solder-side to allow the Cinelabs HVT to fit, as they point out in the installation instructions).")
I am stripping the cab tonight as the kids and I are repainting the inside tomorrow, so hopefully I will get it worked on this weekend... I need to get some more of the voltage regulators as I only had one extra of each...
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