Help with FSP212-3F01 low 24V and 12V!

[cheeky2]

The FSP212-3F01 psu originally came in dead as a doe doe! Replaced all the secondary caps, q7, zd4, r65 which gave me a good 5V standby but no inverter voltage and no 12V.
 Then changed the L6598 ic1 which has given me 20V and 10v when the tv is switched on. The voltages should be 24V and 12V and not  20V and 10V so wondering if its going to be the optoisolator that is causing the drop in the feedback circuit?  As the outputs are 17% down!
 Any thoughts on a solution?

[fix2003]

Hanspree JT261 dead etc
FSP212-3F01 power board

Standby 5volts present but no 12 v or 24v lines after replacing domed electrolytics.

Replaced Q9 (use BC857) and IC1 (L6598D)smd available from chs.
FSP212-3F01 power board

No standby 5volt supply after replacing domed electrolytics - replaced R65 (5R1) smd, ZD4 (15v zener) smd and Q7 (BC847) smd. Q7 works hard so if space allows use a BC 635 for Q7 and solder to the pads.
on the secondary side the 2 1500uf
PSU KIT HAS IN IT
FI T4A FUSE
Q4 8N60
1C2 TEA1532
ZD4 BZV55 C15
Q7 BC848
Q11 BC858
CS21 CS22 both 1500UF 16V
Q9 BC858C
IC1 L6598D
ZD4 was indeed Leakey and replacement restored 15v supply, and set now working, just to note: Q7 BC848 fits in the same way as old smd

[cheeky2]

Just replaced the opto isolator but with the same results! So not the opto isolator. I am more leaning towards a duff L6598d ic so i will swop it over and see what happens for the second time of changing it! I have pretty much replaced all the components apart from IC2 Q4 and Q11. I have another bc858 so i will change Q11 before IC1 i will let you know the results!

[Keith]

Hi,

Have you checked that the inverter is working OK? And have you checked the PSU off load voltages?

Keith

[cheeky2]

Yes checked the off load voltages fed via pin 9 (5v standby) to pin 10 via a 1k resistor. The voltages were no different.
 I must admit i haven't had a chance to change the other components yet though hopefully i will have a chance over the weekend. 
 The inverter i am not sure if it is working as the inverter voltage is only 20V i didn't expect it to operate at this voltage.
 

[Keith]

Hi,

Power the inverter from an external 24v supply and force it on to see if it is working.

Keith

[michael first]

 Hi,

this is the schematic.

[cheeky2]

Sorry to say power supply schematic is for the FSP228 and not the FSP212. Though it may bear more resemblance to the right schematic for it than the one i have for it!

[michael first]

 Hi,
well maybe this one is right.

[cheeky2]

Thanks for the schematic. I have used this together with the one attached to work out that ICS4 is the suspect that is faulty.  They use about three different variations of this power supply in this TV.

ICS4 i think based on the cct diagram is a smd TL432 (SOT-23-3 package) which is a three-terminal adjustable shunt regulator
Does anyone know what the voltage should be between the pins? I anticipate trying to adjust the voltages by replacing  RS39 1.13k resistor and putting a potentionmeter in its place temporarily (hopefullly this will determine whether the ICS4 is faulty).
 I will give it a go tomorrow and will post results

[Turnip]

Hi Cheeky2

Thanks for the shematic, quite different from the usual FSP212-3F01 where I couldn't find your ICS4 as it didn't have one.

Matter of interest, what's a N3252W Tv as don't have it listed/can't find it -

Neon/Naiko/Neovia/Nordmende ?

Thanks again - Chris.

[cheeky2]

Found the power supply from this ViewSonic N3252w-1M apparently they also the same power supply in some of there models in the USA found this out whilst searching for replacement psu on ebay
I will upload shortly the full service manual for it though the psu schematic has very little info on it ie caps or resistor values etc

[vinceroger69]

hi im just working on the same psu just wondered if at all possible you could post the psu scheme up many thanks vince

[cheeky2]

The schematic for the psu is already attached on my previous post. I couldn't upload the full schematic as it wouldn't allow me to do it on this forum in the downloads section!

[gdesmarais]

FSP212-3F01 and FSP228-3F01 use the same board and same schematic. But FSP212 don't populate all the parts.

For the issue of low 24V and 12V, check ICS4. It's an AZ431AC shunt regulator. On my FSP212 unit, the +24V output was pulsing between 0V and 24V. I noticed that voltage across C1 was also pulsing between 160V and 320V, so I suspected the PFC stage. In my case  changing C8 from 2.2uF to 10uF fixed the unit. I noticed that on the FSP228 schematic C1 is a 10uF so i guessed that the FSP212 was derated too much at 2.2uF. Maybe it's enough when capacitor is new but issues arise with aging.

If there is no +12V and no +24V at all, change IC1 L6598D.