BMX MPU 2 flashes

CamaroMurph

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Well after quite a bit of corrosion clean up, I am finally on to step 2 of getting my BMX up and running. U8 socket replaced, all 3 40 pin sockets replaced. I get a flicker and then 2 flashes.

TP1 = 5.15V
TP2 = 12.8V
TP3 = 21.3V
TP5 = 5.15V
TP6 = 10.75V
TP7 = 2.12V

Everything happens the same with just J4 connected to the MPU, or all 4 connectors.

MPU flickers and then flashes 2X. Then goes off.

U8 readings at this point pin:

1 5.15V High
2 30mV Low
3 1.09V Pulsing Low
4 1.13V Pulsing Low
5 30mV Low
6 30mV Low
7 30mV Low
8 0V Low
9 4.54V Pulsing
10 4.54V Pulsing
11 5.38V High
12 5.24V High
13 3.14V Pulsing
14 3.14V Pulsing
15 3.07V Pulsing
16 3.07V Pulsing
17 5.3V High
18 0V Low
19 4.62V High
20 4.33V High
21 5.14V High
22 5.38V High

Suggestions on what to check next would be great.

Murph
 
Thanks Ken.

I placed an order for some of the MPU chips tonight. Never know what might crop up next. Hopefully they will arrive this week and I'll get a chance to try it.

Murph
 
Hey Ken,

While I am waiting for parts let's talk about a couple of other strange things going on.

I have checked voltages at my ISO/PS and all are within the manual tolerance except the 5V and the 11.9V. The 11.9 runs about 12.8-13.5V I replaced the diodes that make up the bridge and it now runs more consistantly at 12.75-13.05V.

The 5V line runs about 7V. I didn't have a new bridge rectifier so I can't replace. Are these values normal?

Murph
 
Thanks Ken. Got my new 5101 today, installed and the game is now mostly working. Looks like most of my corrosion repair is working well also.

Murph
 
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