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WPC test point 6 / R260?

Bertychewster

Bertychewster

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Joined
Aug 30, 2023
Messages
61
Location
West Lothian
I had a fuse blow F105 during multi ball on Fish Tales. Checked wiring etc and then cracked open my until now unused multi meter.
Checked the coil resistance and Ball shooter AE-23-800 was reading 2.7 ohms. It looks a bit rough to be honest. I think if it's below 3 it can be an issue?
Went through all coils on solenoid #1-8 on J-130 and found #6 Left gate A-14406 wasn't getting any reading at all. I've ordered replacement coils for both.
I done the test described here Quick Pinball Driver Board Transistor Test Method everything seamed okay.
It got me thinking, so i googled various causes as I don't want the same happening to my new coils or further damage, so I decided to check the voltages on the power board.
TP1: 14.3v
TP2: 4.8v
TP3: 11.91v
TP4: 0.3v
TP6: 74.4v at first rising over ten minutes to 113.5v. Another thing i noted that the voltage stays for over half an hour or more even after switching off.
TP7: 21.5v
TP8: 17.32v

I found this 50 volts slowly climbing and this Voltage keeps increasing WPC on pinside.
These point to resistor R260, so I checked but my multi meter skills and what setting were letting me down. I checked my BR board and it read 10.5. Nothing on the Fish Tales. This was on the board not isolated.

Question is am I on the right track or have i missed something obvious. I'm inexperienced with this type of issue.
Any input most welcome.
 
Measure resistance across R260 with game off. What do you get? The voltage dropping slowly is normal as there is nothing to discharge the capacitor with the game off.
 
It is 10kOhm so 10 is fine actually. Shouldn’t affect game play but replace anyway as this will discharge the cap when turned off fixing your slow voltage drop.
 
Open reading is wrong, resistor is probably broken. Thought you checked on another machine and got 10.
Are you getting 0 or close to it when shorting the leads? Do you have another machine to cross check on?
 
I don't think I've explained myself here.
I've attached a pic of meter. Shows 0.00 crossed. Fish Tales has the issue.

I cross checked with Black Rose. Same board. It shows 10. No problem.
 

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Change R260. Then re-measure. It's a 20p part, and lots of sources suggest that it's one of a couple of causes....
Elimination my dear Watson...

(to be fair it's not easy to get to, however will be more difficult to get out than get a new one in :) )
 
All Ok, if your BR shows 10 in the 20kOhm setting of your meter its R260 has 10kOhm as it should. Open circuit on the FT means the resistor is shot. Replace.
 
The 50V is NOT regulated so it will read much higher at rest, usually 70~75VDC.

There is also no load on this rail unless a coil is actually activated, it feeds the solenoids, so it the voltage stay there for some time after the machine is switched off.

I suggest watching some YouTube videos on how to use, and MORE IMPORTANTLY - UNDERSTAND! what your meter is telling you.
 
Homepin said:
The 50V is NOT regulated so it will read much higher at rest, usually 70~75VDC.

There is also no load on this rail unless a coil is actually activated, it feeds the solenoids, so it the voltage stay there for some time after the machine is switched off.

I suggest watching some YouTube videos on how to use, and MORE IMPORTANTLY - UNDERSTAND! what your meter is telling you.
Click to expand...
Are you suggesting the Left gate A-14406 which has no ohm reading might be the cause of the rise from 75-113v ?
 
Bertychewster said:
Are you suggesting the Left gate A-14406 which has no ohm reading might be the cause of the rise from 75-113v ?
Click to expand...
I'm not familiar enough with your exact machine to comment meaningfully. I urge you to understand your meter MORE and what it is telling you. It is important to be able to interpret and fully understand the readings you are getting.

They are likely perfectly OK but without a full understanding of exactly what it is you are measuring you can't make a call on the issue OR even if there is an issue, or not.
 
Replaced the 10k resistor and now sits quite happily at 73.5v👍

I have another 49 spare & 100 4.7k that Amazon sent in error. 🤣

Thanks to those who chipped in with some advice.
 
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