Asteroids PCB RAM Fault but ???

[dezbaz]

Fitted big blue previously tested to be OK - Same problem

Tomorrow I will swap power supplies

 

[dezbaz]

dez

could you post a picture of the rev 04 board?
like the one you posted for the rev 06 board.

Thanks

Yes will do

I also have a Taito Asteroids board and will post that pic too

 

[dezbaz]

Rev 01 if needed (Edit: Lunar Lander)


Rev 04


Rev 06 (Used for Multi-Asteroids)


Rev Taito (from a cocktail Asteroids)



I am now going out to swap power supplies to get this cab fixed

 

[dezbaz]

Replaced power supply - Same problem

Replaced Deflection Yoke - FIXED

FAR OUT

I still have an issue

When I try and get full vertical deflection I get deformation at the bottom.
I had the same deflection problem with the old yoke too, so both do not acheive correct height on the screen

I will post a video soon

Any ideas from you guys?

 

[kstillin]

I'm glad you found your problem.

I'm trying to figure out what kind of defect in the yoke could cause something like this. A yoke is just a couple of coils set up in an arrangement to produce a magnetic field from current flowing through them.

Can you see any shorted windings? Nicks, kinks, dents in sections of the windings that otherwise look smooth?

A buddy of mine had an Asteroids board that did something similar- it looked like some of the asteroids 'unwound' when they hit a certain vertical point. I think it was a DAC issue. Anyway, funny about the yoke. How about post if you can see any physical defects.

K

 

[dezbaz]

I'm glad you found your problem.

I'm trying to figure out what kind of defect in the yoke could cause something like this. A yoke is just a couple of coils set up in an arrangement to produce a magnetic field from current flowing through them.

Can you see any shorted windings? Nicks, kinks, dents in sections of the windings that otherwise look smooth?

A buddy of mine had an Asteroids board that did something similar- it looked like some of the asteroids 'unwound' when they hit a certain vertical point. I think it was a DAC issue. Anyway, funny about the yoke. How about post if you can see any physical defects.

K

It's just one for the books

I am an electrician, so it is a while ago I leaned about inductor coils, I am thinking a small short or scratch would cause an imbalance or "back emf" problem

These coils are constantly reversing and collapsing, so balance is the key.

Then again it could just be corrosion on the plug

I will look into it - but later. I have some beta testing to do . . .

 

[DarrenF]

Rev 01 if needed

A Lunar Lander Rev 01...

I've never seen an Asteroids -01 (or -03). Those were the PROM versions.

Your photos are excellent, by the way.

 

[dezbaz]

A Lunar Lander Rev 01...

I've never seen an Asteroids -01 (or -03). Those were the PROM versions.

Your photos are excellent, by the way.

Oops, how'd that get in there ?