HP w2007 PTB-1773 - Where to start?

[MegaOne302]

Re: HP w2007 PTB-1773 - Where to start?

Am I supposed to be measuring DC or AC Voltage at that point? If I place my meter on setting 'DC 2 V' (labeled in photo as 1) the reading goes all over the place plus and minus a few millivolts. If I place it on setting 'AC 200 V' (labeled as 2) it registers at most a .5 for a split second then zeroes for most of the pins. If I release the ground (black) it tends to stay at .5 but not sure that's a valid reading.

Am I doing it right? What does this mean?

The meter is set to read amperage not voltage. Move the Black test lead to the center/common socket. And the Red test lead to the voltage socket.

[maverick530]

Re: HP w2007 PTB-1773 - Where to start?

Can you check the dual diode on heatsink, board number D809
check Solder first if ok then remove and check pins 1 + 2 with diode function both ways, you should have a reading only one way and infinity the other
Repeat the procedure on pins 2 + 3
I will get back to you on the P/Supply flow info, as soon as I can find it

Checked D809 & D810 (while I was at it) and both register a value in only one direction and infinity the other. I suspect these are good.

What's next?

[maverick530]

Re: HP w2007 PTB-1773 - Where to start?

The meter is set to read amperage not voltage. Move the Black test lead to the center/common socket. And the Red test lead to the voltage socket.

This has been corrected as you suggest a while ago, thanks for catching this too.

[Mike7168]

Re: HP w2007 PTB-1773 - Where to start?

Hi,
I have the service manual for HP W1907 which uses the same inverter board,
I can upload the PDF copy if you are interested. Thanks

[maverick530]

Re: HP w2007 PTB-1773 - Where to start?

Hi,
I have the service manual for HP W1907 which uses the same inverter board,
I can upload the PDF copy if you are interested. Thanks

Yes please, I'm very interested if it will have any more information on how it can be fixed. Thanks,

[Bobdee]

Re: HP w2007 PTB-1773 - Where to start?

Checked D809 & D810 (while I was at it) and both register a value in only one direction and infinity the other. I suspect these are good.

What's next?

Have just browsed over the whole thread again and its not clear to me as to whether this P/Supply has been recapped as Plainbill suggested

??? Can you confirm as to whether it has been Recapped or not as the case may be ???
THXs

[Mike7168]

Re: HP w2007 PTB-1773 - Where to start?

Hi,
Tried to upload the service manual last night but the file is too big 3mb, I can email to you. Please email me your address to mselvam1408@yahoo.com.sg.
Thanks

[maverick530]

Re: HP w2007 PTB-1773 - Where to start?

Have just browsed over the whole thread again and its not clear to me as to whether this P/Supply has been recapped as Plainbill suggested

??? Can you confirm as to whether it has been Recapped or not as the case may be ???
THXs

I have not recapped the board yet, although I have purchased all capacitors to do so. I did, however, remove the suspected 2.2uF CapXcon (C828?) and tested its capacitance and it registered fine on a capacitor tester, so I resoldered it back.

I didn't want to recap the whole board just yet because we suspected the MOSFETS on the inverter side were shorting things out. I realize caps can still be bad even though they pass visual inspection, but all of them pass visual inspection. Is there ANY way to test the caps on-board, such as checking the voltage across them when powered like we did with the huge one (C805)?

Is recapping the whole power side of the board the next step? After all, remember, there was never any light on the controls--I'm not getting ANY power out of the board, so I'm pretty confident the problem resides on the power side...

[Mike7168]

Re: HP w2007 PTB-1773 - Where to start?

Hi,
Please see attached service manual page 37 - 42 for power problem.
Thanks

[Bobdee]

Re: HP w2007 PTB-1773 - Where to start?

I have not recapped the board yet, although I have purchased all capacitors to do so. I did, however, remove the suspected 2.2uF CapXcon (C828?) and tested its capacitance and it registered fine on a capacitor tester, so I resoldered it back.

I didn't want to recap the whole board just yet because we suspected the MOSFETS on the inverter side were shorting things out. I realize caps can still be bad even though they pass visual inspection, but all of them pass visual inspection. Is there ANY way to test the caps on-board, such as checking the voltage across them when powered like we did with the huge one (C805)?

Is recapping the whole power side of the board the next step? After all, remember, there was never any light on the controls--I'm not getting ANY power out of the board, so I'm pretty confident the problem resides on the power side...

The trouble with good visual caps is they can still be bad, as you have said above
The trouble with good capatance caps is they may still have bad ESR
I am with you, I do not like recapping when you cant see any visual bad signs on the caps, seen Threads where members have done a total recap and still find that it made no diffrence to there problem ( they must feel sick )
However like you I convinced that its the P/S that is problem, but I suspect that other members thought that you have done a recap or at least the caps that Plainbill sugested (the 3 he circled in red) so I think there some misunderstandig possibly
I would recap plainbills 3 and try it out, if no joy replace the other small one right side of transformer and the 3 big ones by P802 connection and try it out again, If that dont do it recap the rest that are on the P/S side
At least then caps are eliminated if it still dont work
Then I am sure you will then get help with probing the Voltages

[maverick530]

Re: HP w2007 PTB-1773 - Where to start?

Hi,
Please see attached service manual page 37 - 42 for power problem.
Thanks

Thanks to Mike for this very similar service manual for the HP w1907. I've also attached a very relevant power/inverter board overall schematic. I think it's brilliant and I would do well to study it.

[EGuevarae]

Re: HP w2007 PTB-1773 - Where to start?

The trouble with good visual caps is they can still be bad, as you have said above
The trouble with good capatance caps is they may still have bad ESR
I am with you, I do not like recapping when you cant see any visual bad signs on the caps, seen Threads where members have done a total recap and still find that it made no diffrence to there problem ( they must feel sick )
However like you I convinced that its the P/S that is problem, but I suspect that other members thought that you have done a recap or at least the caps that Plainbill sugested (the 3 he circled in red) so I think there some misunderstandig possibly
I would recap plainbills 3 and try it out, if no joy replace the other small one right side of transformer and the 3 big ones by P802 connection and try it out again, If that dont do it recap the rest that are on the P/S side
At least then caps are eliminated if it still dont work
Then I am sure you will then get help with probing the Voltages

I agree with Bob. You had been suggested to replace three caps, and that'ts easy, and would not hurt if they were good (as Bob said and we have found more often than not, even if capacitance is OK and no visual damage is found, ESR can be high and that's the same if not worst than a capacitance difference). Change at least the three caps and start from there.

[maverick530]

Re: HP w2007 PTB-1773 - Where to start?

Sad day,

I replaced all of the caps on the power side and still no joy.

Measuring the voltage across the outputs (with the black ground on the corner screw area) results in a -0.33 v to -0.34 v oscillation.

What else can I try/probe?

[PlainBill]

Re: HP w2007 PTB-1773 - Where to start?

Sad day,

I replaced all of the caps on the power side and still no joy.

Measuring the voltage across the outputs (with the black ground on the corner screw area) results in a -0.33 v to -0.34 v oscillation.

What else can I try/probe?

That negative oscillating voltage is intriguing. A positive voltage would indicate the SMPS is starting, but shutting down. A negative voltage??? Do you have an actual schematic of the power supply / inverter. The block diagram doesn't help a lot.

PlainBill

[maverick530]

Re: HP w2007 PTB-1773 - Where to start?

Attached are the actual schematics for the w1907 power supply (Hopefully, functionally similar to the w2007, because they sure are laid out differently).

[PlainBill]

Re: HP w2007 PTB-1773 - Where to start?

Attached are the actual schematics for the w1907 power supply (Hopefully, functionally similar to the w2007, because they sure are laid out differently).

Well, let's give it a try. The SMPS controller in the schematic is IC901, a LD7552BPS. It should be one of two ICs on the board. Check the voltage from pin 1 (Gnd) to pin 3 (Vcc) with AC power connected. It should be nearly 20 volts.

PlainBill

[maverick530]

Re: HP w2007 PTB-1773 - Where to start?

Well, let's give it a try. The SMPS controller in the schematic is IC901, a LD7552BPS. It should be one of two ICs on the board. Check the voltage from pin 1 (Gnd) to pin 3 (Vcc) with AC power connected. It should be nearly 20 volts.

PlainBill

Assuming pins 1 and 3 are the bottom left pin and 3rd one over from the bottom left (when looking at the IC with the lettering right-side up), I get 0 volts. Sometimes I get 0.01 or 0.02 but really nothing.

Checked the voltage across C805 and I still get 160 volts just as a quick sanity check that I am getting power to the board and my DMM is on and plugged in correctly, but still nothing across pins 1 and 3 of this IC.

Just for kicks, I stuck the negative probe to the screw ground in the corner of the board, and then the red probe on pin 3 and I get 3 volts to 4 volts then -1 and it kinda goes crazy, but I got something. Not sure if this really is accurate but just thought I'd throw that out there.

Does this mean it's bad?

[maverick530]

Re: HP w2007 PTB-1773 - Where to start?

Also, I wanted to make sure, that this was the chip (circled in red)? It has the right number of pins and it says I801 by it (not IC801, same thing?).

From what I can make out the IC reads:

CA 1530A
651D202
MnG7311

[PlainBill]

Re: HP w2007 PTB-1773 - Where to start?

Also, I wanted to make sure, that this was the chip (circled in red)? It has the right number of pins and it says I801 by it (not IC801, same thing?).

From what I can make out the IC reads:

CA 1530A
651D202
MnG7311

Maverick,

It appears this is a radically different power supply board. The most likely part number for the SMPS controller is TEA1530AT. By the way, I have a large magnifier I use to determine part numbers. Even then, it is tricky.

In any event, the first thing to determine is the power supply to the SMPS controller. I've attached an edited version of the picture, check the voltage between the two circled points.

By the way, don't use the metal chassis as a reference when measuring voltages on the line side of an SMPS. I just spent a few minutes trying to figure out what the wave form would be and got a headache.

PlainBill

[maverick530]

Re: HP w2007 PTB-1773 - Where to start?

Maverick,

It appears this is a radically different power supply board. The most likely part number for the SMPS controller is TEA1530AT. By the way, I have a large magnifier I use to determine part numbers. Even then, it is tricky.

In any event, the first thing to determine is the power supply to the SMPS controller. I've attached an edited version of the picture, check the voltage between the two circled points.

By the way, don't use the metal chassis as a reference when measuring voltages on the line side of an SMPS. I just spent a few minutes trying to figure out what the wave form would be and got a headache.

PlainBill

That measures 160.1 v.