HP 1702 shuts down

[BLT]

Got this monitor for free and at first it seemed to work fine. Problem is that it shuts down erratically. When this happens power led goes off too. After unplugging the power for a while it might start again. Sometimes can last for hours, but mostly shuts off after a few seconds.
No caps with visible signs of being bad. Any ideas of what might be wrong with it?

[Dgtech]

Re: HP 1702 shuts down

Change out the four caps around that transformer. They look to be about 1000 uF. Then change the two on the top lefthand side of pic #1. You should be good after that. You should be able to find spares here or digikey - Rubycon or Panasonics.

[BLT]

Re: HP 1702 shuts down

Wow thats one quick reply, thanks!

[Svampapa]

Re: HP 1702 shuts down

Hello!

New member here. I couldn't find any rules on necro posting, but this being the most recent HP1702 thread, and these boards resembling mine the most I thought I'd post my troubles here. Hope that's all right?

I just got it a few days back, hooked it up as a second monitor. It worked flawless for a few days and then it started making trouble.

Same symptoms, goes on for 1 second then goes off. No strange sounds or such. Shining a strong light shows the TFT matrix still doing it's job.


Here is the board, the cap circled was the only obvious culprit. Bulging and looks like he's pushed the bottom as well.

Elite
220μF
25 V
ES(M)105°C
(C)0418

Going to replace him, will probably take the other big ones too. Depends on how easily I can find replacements.

My question though is the L shaped metal profile. What is it? Just a no-nonsense heatsink? Structural integrity?
There are two components screwed to it, three legged bastards looking like monster sized transistors.


Along the bottom of the L profile there is some discolouration like this. Flux? Could this be another culprit? I'm thinking it should have failed in the factory if so. Going to try and clean that off anyway.

[PlainBill]

Re: HP 1702 shuts down

1. It is preferred that pictures be attached to the posting using 'Manage Attachments' (below the text entry area). For several reasons, many of us will not download attachments from external sites.

2. The fault you describe is referred to as 'Two seconds to black'. A common cause is bad capacitors.

3. Elite caps are anything but. I place them in the 'Replace on sight' category.

4. It is recommended that you replace ALL caps, especially those of suspect brands. The sole exception is the large (100uF, 450V) one; it has a very low failure rate. My personal preference is Panasonic FM or FC series; my preferred vendor is Digikey. Other name brands have equally good series; in other countries there may be less expensive vendors.

5. There is no need to be vulgar and cast aspersions on the ancestry of components (in this case, diodes). We can examine the labeling and positively identify their source.

PlainBill

[Svampapa]

Re: HP 1702 shuts down

The pictures are attachments. Typing my first post I seem to have taken too long and had to log in again. For some reason they turned out as links instead of thumbnails. Perhaps I should have uploaded them again.

Does NIC have a good reputation?
I've been looking around a bit and was thinking to use their NRSZ series as replacements.

Although I'd consider myself fairly versed in the English language, it is not my native tongue. I did not mean to offend or be vulgar.

[PlainBill]

Re: HP 1702 shuts down

I have never heard of NIC capacitors. They are not on the Good Caps list. I suggest checking the FAQ, especially the 'What Caps should I Buy?' and 'Where can I buy Them' threads.

PlainBill

[jetadm123]

Re: HP 1702 shuts down

NIC NRSZ caps are on the good caps list. They're not as well known as Panasonic, Rubycon, Chemi-con, etc. I have used the NRSZ series without any problems.

[PCBONEZ]

Re: HP 1702 shuts down

'NIC' is NIC Components.
High quality Japanese caps.
Smaller company so not so well known.
http://www.niccomp.com/company/index.php
http://www.niccomp.com/products/prod...c%20Capacitors

[PCBONEZ]

Re: HP 1702 shuts down

Don't confuse the NIC Components NRSY series [good caps] with the NRSY -brand- [crap caps].

[PCBONEZ]

Re: HP 1702 shuts down

3. Elite caps are anything but. I place them in the 'Replace on sight' category. PlainBill

Agree completely.
'Replace on sight'

[Svampapa]

Re: HP 1702 shuts down

Allright. The Elites went out, and in the NICs went in.

No dice. Still one second to black.

Having spent ~$50 (VERY expensive shipping) on this little project already I'm done. By todays standards it is a small monitor. I was going to use it as a second display, but for $50 I could have gotten a used larger monitor. Stop-loss is in effect.

Just smelling the solder melting once again was worth it though. I had fun poking around the boards, and just once again thinking about these minute components that on a very basic level is so integral to our lives these days was fun.

Thanks for the input, see you around!

[PCBONEZ]

Re: HP 1702 shuts down

$50!!!
You ~really~ need to find a better place to buy caps.