Neotec NT-27E ? issues

pun84

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I've got a San Fransisco Rush with a chassis that is either NT-27E or 2701.. I am not 100% sure.. but it had originally blown the hot.. I then swapped in a new flyback (MRCFT-249) and d1879 HOT.. It worked for about 30 minutes before blowing the hot again...

I isolated and checked out the power supply voltages.. they all check out good.. is it possible my replacement flyback is bad? Or my yoke has burned up?

I checked the horizontal inductance of my yoke and it reads pretty low... about 0.265mH

My board doesn't exactly match up perfectly with the normal schematics available on arcade archive.. namely R424 (820ohm 5W) which is a 3.3Kohm 5W in the schematic..


 
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You need to change those orange HV caps too. Off the top of my head I think there's
a small 1.6kv cap right in front of the HOT that needs to be changed as well.

JD
 
there's an orange 560pF 2kV (C421) cap right next to the FBT which checks out okay, is that the one you're talking about?
 
cap kit?

If any chassis has OEM parts
it needs a cap kit for these older chassis.
B+ is too high 125 to high looks like its adjusted to end.
need to replace caps first then adjust dc
the small aux board has the HV caps on them
their not on the main board..they maybe good.
Inspect the remote board for crack in pots and bad connections
on the board and main chassis.
 
Most of the caps are OEM, I did pull them and check capacitance/ESR they check out ok. I changed out the ones that didn't, the red/orange HV caps also checked out as ok capacitance wise, not sure if there is something else I should check on them though as none were shorted..


I think my chassis is actually a 2701 and not a 27E.. I downloaded the NT2700 Li-Chin version.pdf Ken Layton had posted on another forum, and the parts that aren't matching up for me in the 27E manual are matching up in this one..

I really wish these manufactures would label their boards better.. The cardboard neckboard backing on my chassis says 27E !!!! =(
 
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*update* Fixed.. replaced HOT with a BU4530AL .. set B+ to 113VDC at R424.. HV is around 20kV.

Only problem I seem to have now is that Q3 & its heatsink on the pincushion board gets significantly hot.. not sure what is causing that!
 
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