kiphartzell
New member
Ampilfone Deflection "fish-hook" diode mod?
I have a green Amplifone deflection board that I am getting ready to rebuild with suggested mods. Searching the forums and other on-line documentation, I see some potential conflicting information that I hope someone can clarify regarding the "fish-hook" zener diode modification.
The original Atari Field Service bulletin calls for
2 - 1N754A 6.8V Zener Diode
2 - 1N756A 8.2V Zener Diode
Note: Gregg Woodcock's Atari Vector Monitor Repair Upgrade doc reprints the same info from the Field Service bulletin
Michael Kelley's Amplifone HV & Deflection FAQ and Guide calls for
4 - 1N5342B 7.5v 5 watt Zener Diodes (though Ataricade.com points out that 1N5343B is the right part # for the deflection board diode mod (not 1N5342B since 1N5342B is really a 6.8v diode)). I would agree that 1N5343B is the proper choice, if a 7.5v should be used?.
Also, from a Vectorlist archives, I read an append that suggested using 2 x 1N5342 and 2 x 1N5344 for this mod.
So what is the best approach to take? Using a 6.8v/8.2v combination of diodes or all 7.5v diodes?
I have 1N5342B diodes and 1N4738 (Bob Roberts replacement for a 1N756A) diodes in stock. 7.5v diodes would need to be ordered.
For the sake of discussion:
1N754A (0.5w) = 1N5342B (5w) 6.8v zener diodes
1N5343B (5w) 7.5v zener diode
1N756A (0.5w) = 1N4738 (1w)= 1N5344 (5w) 8.2v zener diodes
I have a green Amplifone deflection board that I am getting ready to rebuild with suggested mods. Searching the forums and other on-line documentation, I see some potential conflicting information that I hope someone can clarify regarding the "fish-hook" zener diode modification.
The original Atari Field Service bulletin calls for
2 - 1N754A 6.8V Zener Diode
2 - 1N756A 8.2V Zener Diode
Note: Gregg Woodcock's Atari Vector Monitor Repair Upgrade doc reprints the same info from the Field Service bulletin
Michael Kelley's Amplifone HV & Deflection FAQ and Guide calls for
4 - 1N5342B 7.5v 5 watt Zener Diodes (though Ataricade.com points out that 1N5343B is the right part # for the deflection board diode mod (not 1N5342B since 1N5342B is really a 6.8v diode)). I would agree that 1N5343B is the proper choice, if a 7.5v should be used?.
Also, from a Vectorlist archives, I read an append that suggested using 2 x 1N5342 and 2 x 1N5344 for this mod.
So what is the best approach to take? Using a 6.8v/8.2v combination of diodes or all 7.5v diodes?
I have 1N5342B diodes and 1N4738 (Bob Roberts replacement for a 1N756A) diodes in stock. 7.5v diodes would need to be ordered.
For the sake of discussion:
1N754A (0.5w) = 1N5342B (5w) 6.8v zener diodes
1N5343B (5w) 7.5v zener diode
1N756A (0.5w) = 1N4738 (1w)= 1N5344 (5w) 8.2v zener diodes