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CR 1020 Power supply gremlin

What value of resistor is installed in the R731 & 732 position ?
 
If C714 was shunted it would also bleed off your -25vdc power supply..
 
For comparison took same esr readings on C713 and C714. Both read approximately 100uf and 0.56 ohms. Do you still think I need to pull R731 and 732?
 
Nuklhed said:
For comparison took same esr readings on C713 and C714. Both read approximately 100uf and 0.56 ohms. Do you still think I need to pull R731 and 732?
Click to expand...
No.. Make sure TR704,708,714 & TR715 are all properly installed.
 
Hey again Nuklhed,
Did you say that your Relay board was a fabricated board? If so, I'm wondering - regarding TR704. TR708, TR714, & TR718; Do you recall the model#'s those are in your new pcb? I wonder maybe if an unsuitable replacement may have been used.

Arch
 
arhargi said:
Hey again Nuklhed,
Did you say that your Relay board was a fabricated board? If so, I'm wondering - regarding TR704. TR708, TR714, & TR718; Do you recall the model#'s those are in your new pcb? I wonder maybe if an unsuitable replacement may have been used.

Arch
Click to expand...
Was there and issue with these boards ? Arch ?
 
I don't know, my CR-2020 board is OEM, with all TR's replaced, all caps replaced, along w/a new relay, and about a dozen R's or so. Below are the replacements I used.

Original Pin-out Replacement Config. Pin-out

2SD400 ECB SC2383OTA NPN ECB

2SC1213A ECB SC2383OTA NPN ECB

2SA673A ECB KSA1013YBU PNP ECB

2SC1890 ECB KSC1845 NPN ECB

2SA844 ECB KSA1015YTA PNP ECB

2SD234 BCE TIP31A NPN BCE TR712, TR715

2SC1918 ECB KSC1845FTA NPN ECB

2SB544 ECB KSB1151YSTU PNP ECB

Of course, these may not apply to the CR-1020, But more than likely they're an exact fit.

Archie
 
Yes, I am using the boards that jayfree designed for use in the 2020. I currently have the new boards installed in a 2020 and they work beautifully. I made a huge assumption from my research that the relay board in the 1020 was identical to the 2020. I’m beginning to wonder. Upon reviewing the schematics for both models I did notice a difference in grounding, but electrically it is accounted for on the new boards.

For info, these are the transistor replacements I used
TR701, 705, 707. KSC2383O
TR702, 708. KSA1013Y
TR703, 713. KSC2383Y
TR704, 711, 714. KSA1015Y
TR706, 709, 710, 717, 718 KSC1845
TR712, 715. TIP41C

I have the board out now, looking at solder connections etc. I’m fighting the urge to pull the relay board out of the 2020 and put it in the 1020 and see what happens…..

And again, sooooo grateful for you fellas time and expertise!
 
Know what really sux.. And major error in the CR-1020 schematic. It has the CR-2020 power supply illustrated in the 1020 schematic. I've only done a few 1020's a few years ago. Mostly 2020's & 2040's were on the bench.

That said. I think that board should work .
 
According to the two service manuals parts list.. It says that the PS circuit board #1 is the same part number for both models. NA06899
 
Ok…ready for this? I succumbed to weakness. Took the relay board out of the 2020 and installed it in the 1020. THE PROTECTION RELAY CLOSED RIGHT IN!! But….check out this mess
+NB 48.4 vdc
-NB -26 vdc
-13. -1.98 vdc
+25. 37.9 vdc
-25. -14.2 vdc

Did this show us anything? I’m more confused. I think I need to trace every wire connected to the relay board and make sure I have it right.
 
I'm thinking about that 6 pi plug-in connector. Maybe those soldered connections need to be reflowed.
 
You mentioned something earlier on about grounding differences between these 2 fabricated Relay boards. I'm wondering if that might be what's hosing-up some of your voltage readings.
 
I do believe that although the boards are supposed to be identical per parts list I think that the 1020 needs to be terminated differently. Over the last couple days I’ve been doing a side by side comparison of the schematics. I have noted that there are a couple of differences in the grounding scheme on the two machines. I’m not sure yet how it makes a difference. My”guy” is sending me a functioning oem 1020 and I will do some detailed forensics to see if I’m doing something wrong terminating the new boards. I’ll be sure and post my findings. In the meantime, thank you again Arch and Avionic for your help.
 
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