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Hantarex Polo/2 25-28 Dead - how to test B+ (SOLVED)
perjmolsen:
Hi
I have now put in a new flyback, and my +B at is way high 195V-200V
If I remove solder at pin3 at flyback, and put on a bulb, I get 145V B+
If i follow the Hantarex polo flowcart, it says to replace C114 (in my case I assume that is C18 it is at the same spot)
I have replaced the cap, but the B+ is still high with the flyback in place.
So the next step, is to test B+ at the collector T114 (in my case T22) its is also high.
Then I have tested for 12V at pin1 on IC104 (in my case IC6) there i only have 1.3V
So it seems that my 12V is missing, so where do I check for 12V an my Hantarex Polo/2 chassis - the normal Polo is TP10 - but no TP at my Polo/2
It would be so wonderful if I had a schematic over a Hantarex Polo/2, so that i could find the components on the 12V line
princess prin prin:
Your B+ is spot on so the power supply is fine and it makes no sense to replace parts there.
The problem is something in the horizontal drive circuit (starts at pin 4 of the TDA2595 and ends at pin 4 of the flyback) is not working as it should so the flyback does not work or it shuts off immediately because of the x-ray protection. Most likely some component connected to the HOT collector line is faulty or there's a crack in that area or the solder joints are bad.
Don't use the Polo schematics for reference as that chassis has different parts. The IC that generates the H drive pulse on the Polo is a TDA2593 but on the POLO 2 it's a 2595. Different pinout so your 12v check was pointless. The Polo 2 schematics you can find with google are of the automatic frequency switch version but most things are the same.
princess prin prin:
Also, to use a 7191 flyback on this chassis you need to change the jumpers as shown here:
http://www.ukvac.com/forum/forum_posts.asp?TID=368371&KW=&PID=1120284&title=the-new-hr-diemen-flyback-transformers#1120284
grantspain:
polo 2 auto schems
perjmolsen:
Hi Grant and Princess prin prin
Thanks for all you help :cheers: :notworthy:
I have tried to see if I can figure out why my B+ is so high (185-190V) when the fly is mounted.
I have 12V at D12 (12V on the striped end and 11V at the other end) so my 12V is present.
I have tested D12 out of circuit, it tests fine.
Pulled out t15, t16 , t17 and t18 and tested them, they all test fine.
Found a bad trace at IC5 (TDA2595) - fixed it but still the same high B+
:hissy: