Atari Amplifone MC1 Revisited

PeRFiDiouS

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I am looking to come up with a replacement for the MC1 component on the Atari Amplifone HV unit. It is needed for the new Amplifone HV reproduction units and to keep the original ones working. This component is crucial to the HV units operation and seems to fail as much or more than the flyback.

The component is a combination of 3 coils/chokes.
Here is some information reposted from the Vectorlist archives:


From: Jess Askey
Date: Tue Feb 08 2000

Hi all,
I decided to smash up one of my Magnetic Correction Units to see what was
inside since I didn't think it has been documented here. It came apart quite
nice after sitting in the freezer all day. What I found was sort of puzzling (to
me at least) can anyone help explain this....



12 turns air core (cylinder)
Terminal 1 0-----+------@@@@@@@@-------------------+------0 Terminal 2
| |
| |
|-----@@@@@@@@---------@@@@@@@@---|
12 turns 8 turns
solid core solid core
(cylinder) (half circle)


Im not sure of the guage of the wires on each inductor exactly.


What is the effect of having different core'd inductors in series/parallel
like this?


--------------------------------------------------------------------------------------------------------------------


From: Joe Bachmann
Date: Sat Mar 30 2002

All,


I had a HV board here without an MC1 on. So, with the knowledge of what Zonn
had put into the Amplifone FAQ I decided to try something to replace MC1.


Now having a few old Pac filter boards lying around I removed 3 of the coils
off the board. I soldered this together in a triangle end to end:


/\
/ \
-----


After this, I placed it into the MC1 position just as above. This gives you one
coil with two in parallel with it. The HV assembly I used was otherwise working
with a real MC1.


I placed this into a Star Wars cabinet and it came right up! My HV was HIGHER
than with a real MC1 - 20kv vs 19.5kv. After adjusting this down, I played a
few games of Star Wars. After turnign off the machine, I was very suprised to
find that my HV board seemed to be running cooler than with a regular MC1. Now,
I will need to test this in the long time and be sure it last 8-16 hours
straight.


JB



Has anyone tried the method above with any success?
Joe B. has a spotty reputation at best but I do not see any reason he would just make this up. I have the parts mentioned above and have thought about trying this but really wanted some more input and any information others have in this area first.



..
 
I am looking to come up with a replacement for the MC1 component on the Atari Amplifone HV unit. It is needed for the new Amplifone HV reproduction units and to keep the original ones working. This component is crucial to the HV units operation and seems to fail as much or more than the flyback.

The component is a combination of 3 coils/chokes.
Here is some information reposted from the Vectorlist archives:






Has anyone tried the method above with any success?
Joe B. has a spotty reputation at best but I do not see any reason he would just make this up. I have the parts mentioned above and have thought about trying this but really wanted some more input and any information others have in this area first.



..

I have all the gear to do this including the correct guage wire and round toroids etc

In a few weeks we will know (I have enough gear to make 25 sets)

My new Amp boards have a spot for the 3 chokes
 
Last edited:
Parts Source Information

I have all the gear to do this including the correct guage wire and round toroids etc

In a few weeks we will know (I have enough gear to make 25 sets)

My new Amp boards have a spot for the 3 chokes

Could you please post the part source information. This way others can order these parts and make them also.

I assume if they do work the 25 pieces you are making will be sold to buyers of the reproduction pcb. This part is needed to keep the original units going also and the information would serve many in the hobby.
 
Could you please post the part source information. This way others can order these parts and make them also.

I assume if they do work the 25 pieces you are making will be sold to buyers of the reproduction pcb. This part is needed to keep the original units going also and the information would serve many in the hobby.

Yes, it will be documented :)

I suggest waiting till it is proven first, to limit duplication / and errors

I will share, I was actually making MC1s to fit into NEW whole HV Boards (Complete Loaded Repro boards), rather than just spare parts

Once my proto PCBs arrive in about 1 week I will load it up with gear and MC1 parts and happily post the results
 
Last edited:
MC1 reproduced - no problems


Before (Orig MC1)
MC1-03.jpg


Fitted to board
MC1-04.jpg


After (New MC1)
MC1-05.jpg
 
MC1 reproduced - no problems

This is great news. Good work! ;)

Could you please post the information on what you used and where you sourced the parts. It seems like a simple process and I know this part will bring MANY original Amplifone HV units back to life. I have 4 on the shelf that currently work but are missing this part. Please post this information so everyone in the hobby can benefit from this.
Thank you.




..
 
Hey Perf

I made a mistake

The toroidal ferrite uses 23 SWG (0.63mm) NOT 0.7mm as stated prev. That would explain the problems I had with the deflection board transistors etc under light load

Apologies
 
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