1987 Macintosh Plus (Platinum)

[Kai Robinson]

1 to 3 = 1.5Meg
2 to 4 = 1.5Meg
5 to 7 = 1.5Meg
5 to 8 = 1.5Meg

All measured in circuit :/

 

[RetroTheory]

That makes no sense to me, even if it's the wrong coil they should not be the same. I can send you a tested flyback if you want

 

[Kai Robinson]

Out of circuit....nothing at all!

 

[RetroTheory]

Damn, unless they are rectified coil output , have you tried a diode test across the pins either way, it's the wrong coil anyway but might explain why you are not getting continuity and may explain the cap popping

 

[Kai Robinson]

Did a bit more measuring:

between pins:

1 + 4 = 1.5 ohm

1 + 5 = 1.5 ohm

2 + 3 = short

2 + 7 = short

2 + 8 = short

3 + 7 = short

3 + 8 = short

4 + 5 = short

 

[RetroTheory]

Better and much worse, there should be no connection at all between 1 and 5 for a start . Not to mention the rest .

 

[Kai Robinson]

BTW just to clarify - this is the one i purchased: https://www.donberg.co.uk/descript/h/hr_42086.htm

 

[RetroTheory]

Yep, I gathered that , it's a pity https://hrdiemen.com/ is down . That may have the schematic of the flyback . I've searched webarchive and Google cache with no hits.

 

[Kai Robinson]

@techknight dug this up in the discord:

 

[RetroTheory]

Sorry I ment more like this here but for that flyback you got
Just an example

Line Output Transformer / Flyback: HR7807 (HR 7807) - RTRNF1643CEZZ / 0026510501 SHARP LINE OUTPUT TRANSFORMER (LOPT)/ FLYBACK

hr 7807, rtrnf1643cezz / 0026510501 sharp line output transformer (lopt)/ flyback

m.donberg.ie

 

[Stephen]

From two known-good analog boards (in-situ):

"TAI-HO TH1565" flyback on a 630-0102 Analog Board

• 1 to 3 = 0.4 Ω
• 2 to 4 = 0.8 Ω
• 5 to 7 = 4.3 Ω
• 5 to 8 = 1.4 Ω

• 1 + 4 = .9 Ω
• 1 + 5 = O.L.
• 2 + 3 = .7 Ω
• 2 + 7 = 17.56K Ω
• 2 + 8 = 4M Ω (some fluctuation)
• 3 + 7 = 93K Ω (some fluctuation)
• 3 + 8 = 3.5M Ω (some fluctuation)
• 4 + 5 = 3.5M Ω (some fluctuation)

Unmarked flyback on a 630-0102 Analog Board

• 1 to 3 = 0.7 Ω
• 2 to 4 = 0.8 Ω
• 5 to 7 = 4.2 Ω
• 5 to 8 = 1.5 Ω

• 1 + 4 = 0.8 Ω
• 1 + 5 = 3.5K Ω (some fluctuation)
• 2 + 3 = 0.8 Ω
• 2 + 7 = 20M Ω (some fluctuation)
• 2 + 8 = 10M Ω (some fluctuation)
• 3 + 7 = 3.5K Ω (some fluctuation)
• 3 + 8 = 3.5K Ω (some fluctuation)
• 4 + 5 = 3.5K Ω (some fluctuation)