From Newsgroup: rec.games.pinball

I'm fixing a Strikes and Spares and a Mata Hari , both need the Solenoid / driver board repairs.
1. Can a 1N5275B zener diode replace a 1N5275A ? They appear to be the same when I look at the specs but I can't be sure.I have plenty of the "B" ones.
2. On one of the boards, I did partial replacement of the components Q22,Q23 R51,for the High Voltage section and the displays worked correctly for one boot only. R51 did not burn but remained too hot to touch. I then replaced both diodes (1N4004 and 1N5275A) and Q21 and remaining resisters.
Voltage on TP2 and TP4 is the same at 240V I think I may have burnt something in the circuit by not replacing all components at the same time. Also the large caps were replaced.
Andy B.
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From Newsgroup: rec.games.pinball

On 2020/07/26 11:49 a.m., brescia1959@gmail.com wrote:

I'm fixing a Strikes and Spares and a Mata Hari , both need the Solenoid / driver board repairs.

1. Can a 1N5275B zener diode replace a 1N5275A ? They appear to be the same when I look at the specs but I can't be sure.I have plenty of the "B" ones..

The "B" version has tighter specs, it will be fine.

2. On one of the boards, I did partial replacement of the components Q22,Q23 R51,for the High Voltage section and the displays worked correctly for one boot only. R51 did not burn but remained too hot to touch. I then replaced both diodes (1N4004 and 1N5275A) and Q21 and remaining resisters.

Generally speaking rebuilding these HV units is replacing all components except possibly the main HV cap. I also recommend leaving the output
fuse out of circuit until you know the supply is adjustable. Leave it
running with no load for a while to check it is stable.

Make SURE the output fuse is correct, and check that the input HV fuse
is the correct value too!

Voltage on TP2 and TP4 is the same at 240V I think I may have burnt something in the circuit by not replacing all components at the same time. Also the large caps were replaced.
Andy B.

John :-#)#

--
(Please post followups or tech inquiries to the USENET newsgroup)
John's Jukes Ltd.
MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
(604)872-5757 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."
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From Newsgroup: rec.games.pinball

On Sunday, July 26, 2020 at 8:53:58 PM UTC-4, John Robertson wrote:

On 2020/07/26 11:49 a.m., brescia1959@gmail.com wrote:

I'm fixing a Strikes and Spares and a Mata Hari , both need the Solenoid / driver board repairs.

1. Can a 1N5275B zener diode replace a 1N5275A ? They appear to be the same when I look at the specs but I can't be sure.I have plenty of the "B" ones..

The "B" version has tighter specs, it will be fine.

2. On one of the boards, I did partial replacement of the components Q22,Q23 R51,for the High Voltage section and the displays worked correctly for one boot only. R51 did not burn but remained too hot to touch. I then replaced both diodes (1N4004 and 1N5275A) and Q21 and remaining resisters.

Generally speaking rebuilding these HV units is replacing all components except possibly the main HV cap. I also recommend leaving the output
fuse out of circuit until you know the supply is adjustable. Leave it running with no load for a while to check it is stable.

Make SURE the output fuse is correct, and check that the input HV fuse
is the correct value too!

Voltage on TP2 and TP4 is the same at 240V I think I may have burnt something in the circuit by not replacing all components at the same time. Also the large caps were replaced.
Andy B.

John :-#)#

--
(Please post followups or tech inquiries to the USENET newsgroup)
John's Jukes Ltd.
MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
(604)872-5757 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."

Thanks for the confirmation John, and the helpful tip of testing without a load. Andy B.
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From Newsgroup: rec.games.pinball

On Monday, July 27, 2020 at 8:38:36 AM UTC-4, bresc...@gmail.com wrote:

On Sunday, July 26, 2020 at 8:53:58 PM UTC-4, John Robertson wrote:

On 2020/07/26 11:49 a.m., brescia1959@gmail.com wrote:

I'm fixing a Strikes and Spares and a Mata Hari , both need the Solenoid / driver board repairs.

1. Can a 1N5275B zener diode replace a 1N5275A ? They appear to be the same when I look at the specs but I can't be sure.I have plenty of the "B" ones..

The "B" version has tighter specs, it will be fine.

2. On one of the boards, I did partial replacement of the components Q22,Q23 R51,for the High Voltage section and the displays worked correctly for one boot only. R51 did not burn but remained too hot to touch. I then replaced both diodes (1N4004 and 1N5275A) and Q21 and remaining resisters.

Generally speaking rebuilding these HV units is replacing all components except possibly the main HV cap. I also recommend leaving the output
fuse out of circuit until you know the supply is adjustable. Leave it running with no load for a while to check it is stable.

Make SURE the output fuse is correct, and check that the input HV fuse
is the correct value too!

Voltage on TP2 and TP4 is the same at 240V I think I may have burnt something in the circuit by not replacing all components at the same time. Also the large caps were replaced.
Andy B.

John :-#)#

--
(Please post followups or tech inquiries to the USENET newsgroup)
John's Jukes Ltd.
MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
(604)872-5757 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."

Thanks for the confirmation John, and the helpful tip of testing without a load. Andy B.

Before re-installing the high voltage fuse, you should also reduce the HT voltage to a value which is more appropriate for old displays. I use about 160 VDC, and make sure that the displays turn on. They will not be as bright as before, but will last a lot longer. I have had displays running for more than 15 years (at 160 VDC) without any losses of segments or appearance.
Yves
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