G05-802

Zinfer

Well-known member
Joined
Apr 19, 2008
Messages
4,497
Reaction score
32
Location
Lima, Ohio
Asteroids plays blind. Spot killer LED lit. Blows 2amp F700 fuse. F600 is always fine. Ran a cap kit. Replaced all chassis mounted transistors and laid plenty of heat sink compound and mica's. I checked all Transistors before throwing the monitor back in, no continuity to the frame. After plugging in, turning on, blew F700 fuse, Spot killer lamp lights. I double check the chassis transistors and both 2N3716's show continuity to monitor frame while the 2N3792's do not. Oscope X and Y out giving good signals from PCB. Appears fine and game is in attract mode.
Unplugged edge connector leading to main harness. Transistors no longer show as shorted to the monitor chassis.
Why would 2n3716's show isolation from frame, then when monitor plugged in, they show continuity? I'm thinking it's a deflection board through hole transistor. I've looked at 608 and 708 diodes. Nothing appears blown or shorted. If I leave it plugged in too long it'll blow the F700 fuse again. (3rd 2amp fuse).
 
I've also tried another deflection board. In both cases, if I unplug P500 The 2N3716's no longer meter as shorted to the chassis. So is this an HV issue?
 
Asteroids.

This Asteroids does not use a bridge rectifier in the power supply assembly. It uses 2 diodes mounted on a circuit board mounted below big blue. The components and board look good. I could replace the diodes and I'm thinking these are them:
http://www.newark.com/multicomp/p600a/standard-diode-6a-50v-p600/dp/87K2188
I just replaced Big Blue and it had no impact.

Sorry about that. I have been working on ADs, Centipedes and Pole positions lately. The 2 diodes are easy to check with a meter. Set it to doide test and they should flow current in one direction but not the other. The big blue, when it is failing will not put out enough current. It will not blow fuses.
 
Getting 9.87 on the one side and like, practically nothing on the other. Both diodes giving the same readings.
 
is it possible to put the anode rectifier in backwards? I did not repack it with rtv at the time, but from that point on whenever I power up, I get sparks, waft of smoke until I hit shutoff. Does the stripe go towards the secondary anode/tube or stripe side to transformer?
 
never mind, I think I got it. stripe towards CRT. I packed it with rtv and it should be good now. 2 chassis transistors are showing short 2n3792's at Q609 and Q709 but only when P500 is plugged in to the deflection board.
 
I thought I had it taken care of. After removing the monitor, taking it to the bench, reversing the hv diode so the stripe is towards the CRT and packing it with rtv silicone, returning it to asteroids, I'd apparently forgotten to plug in the hv cage to the monitor harness. As soon as I did and powered up, it began arcing through the rubber at the socket on the transformer side. Looks like I fried the hv diode having it in backwards for a moment. Either that or it takes the rtv silicone a while to setup. Powered down, ordered hv diode. I can still work on this transistor issue with the hv unplugged though.

There's only two things it can be, either the power brick or the deflection board itself. And I just finished checking the voltages on the diodes at the brick.
 
802

The chassis transistors shorted to the case is definately a problem. The stripe goes toward the CRT. Most meters will not put out enough to test the HV diode. The sparks are kinda scary honestly.
 
Yea, shot myself in the foot on that one. There is one silver-lining there though, as the HV cage was unplugged from the harness, that ruled out anything in the HV affecting whatever is shorting these chassis transistors. Unplugged the pcb, unplugged the ar2. That ruled alot out.
However, with the cabinet unplugged from the wall, no power and with P500 plugged in, I'm getting a short in those two transistors. When I unplug P500 no more short. ?
 
Ok, still waiting for parts.
Hopefully this week I'll finally recieve the Hv diode. I'm also waiting on replacement diodes for the power supply rectifier. I've also been in contact with arcadecup because I'm getting to the point of frustration on this Asteroids. I have a firepit in my backyard and I've explained to the guilty party that he will be sledged first.
 
Is there a G05-802 transistor kit for the onboard deflection board transistors? Kind of a shotgun-kit?
 
Trans

I am not sure. I have emailed Bob Roberts with stuff like this before that does not come in a kit and he will assemble the pieces you need and sometimes offer advice.
 
Hey Zinfer, if you hit a dead end and are looking to spend dont hesitate to send it in. Ill set your monitor right and then some. Thanks & good luck.
 
Yea I've hit that dead end. Most of it is the wait for parts. And I'm noowhere near skilled as Chad. I just want this God Blessed Cabinet to work just as well as the other's that I have in my arcade. I've been working on it for so long, getting it fixed, just to have it fail again a week or two later. And it's always the vector. Either a TL082 goes or the deflection board.
I'm on my last half month wait for parts. I filled out the form Chad. I'll be taking the monitor out of the cab and unmounting the tube. I should have it shipped out by the end of this week. Just tired of working on it ALL the time. I'd like to play it more than work on it. I really need to move on to other cabinets.
Please please please try to get this thing stable; so I don't have to cross my fingers everytime I hit the on switch.
I'd like to sell this board as well and hope for the best in a bulletproof board. I swear I've replaced 4 tl082's in the past 2 mos.
 
Okey doke, I swapped in a set of rectifiers at the power supply chassis today. NTE5814's. Axial lead 6A 400v. So it's not big blue, it's not the rectifier, the game plays blind so I'd say all voltages are just fine. I still get cage arcing when I plug in the monitor because I am STILL waiting on Diodes. They are coming from Red China with a shipment of tea.
I'll probably recieve them when I get the monitor back from Arcadecup.
 
Back
Top Bottom