Polo Monitor

[worm]

 I have a polo monitor that has a ticking sound,check the it's good replace c107 c108 checked d105,107,108 Z102.
 What do I look for or what do I check?

[Ken Layton]

All Hantarex models are well known for needing lots of capacitors. Install a capkit first then see how the monitor works.

[grantspain]

whats the history on this monitor?

[worm]

got cap kit still have a ticking sound realy need this one working.

[grantspain]

look at the other polo post,change  t114(bu508a if its polo1 chassis,also you may need to change c172 if the ht is all over the place)

[worm]

 "Ticking".  This indicates the power supply is trying to power up but can't - either because of no load, excessive load (shorted H.O.T or flyback), or bad caps in the power supply section.

If no ticking is heard, it is probably total destruction of the Switching power supply - usually with a blown fuse.

First, you need to determine if its a switching power supply problem or the other part of the monitor.  To do this, lift the right side of L103 off the board, and connect a 55 or 60W incandescent light bulb across it and ground (right heat sink).  Then plug it in.  It should light the bulb in a few seconds.  IF it doesn't, then it a power supply problem.

WARNING!  Do not probe the switching power supply section with an oscilloscope without using an Isolation transformer as this part of the monitor is considered a Hot Chassis. It is okay to make voltage checks with a DVM but don't touch anything metal with your hands.

If power supply problem (components under RF cage):

Check for shorted MosFet (usually blows main fuse)          no blowen fuse
Check for shorted diodes - especially D105, D107,108,109, ZD101. checks out okay
Check for open Resistors - especially R111,112,113    checks okay
If ticking: Bad caps especially C106 and C108*   replaced

IF the light lights - bad Horiz Circuit:
Check H.O.T. T114    Replaced
Replace Flyback (available from MCM Electronics for about $29)

* if you only have C107, you are looking at a 220V unit.  While it may be labeled that it will run from 90-240VAC, I have found as they were out, they won't - should be converted to 120V style if using 120VAC.

As I said, there are plenty of other portions that fail.  Here are a few more common ones:

Burns R167 - Bad Vertical IC TDA1675 (also if vertical line)

No horizontal width control - Bad D134

Another item we see a lot because the boards are shipped to us for repair is broken traces - especially around the flyback and where the RF cage is mounted to the PCB.  They may be tuff to see on underside but usually you can see the cracked PCB from above

checked all above and still bave a ticking sound,what do I do now and where do I look?

[grantspain]

blimey you pretty much got it covered by the last post-so you have done everything denoted,even changed the flyback-what about ic 101 and damage around r219 and checked 130v on that resistor-i had a similar fault on a polo and changes all the caps in the psu not just the ones previously stated,t114,c172 also you need to remove one side of a diode to read it correctly but you already know that i guess