echostar hds-600

[bootlegger17]

Re: echostar hds-600

swapped C484 with same and ranging still occurs.
I take it ranging of a cap is a bad sign, or can it simply mean something before it has failed?
In which case, I will need to check/replace the bits inbetween the big cap and this one thats ranging. what type of things can make a cap range?

Jason

[Agent24]

Re: echostar hds-600

It can indicate that the capacitor may have low capacitance or high ESR and can't hold a charge properly.

If the capacitor is the supply filter capacitor for the PWM controller, the controller can lose power every time it tries to start up resulting in malfunction of the PSU.

[tom66]

Re: echostar hds-600

That cap bouncing about indicates the circuit is trying to start, but failing.
(It's sort of equivalent to a car trying to start, but not able to.)
This can be due to a number of faults: bad switching controller IC, bad start up capacitor, shorted diode on the output side, excessive load on the output side, and a few others.

[bootlegger17]

Re: echostar hds-600

arrghhh
This is why i dont like playing with PSU's....
Figured I better check some of the items between the good large cap and the fluctuating small cap, and one of the items was a Power IC, model Q0456R.

Looking at the bottom right of this IC there is a small mark, so I suspected that may have blown. Decided to test on top side and during my testing, I think I managed to short pins 1 + 3 and got a big bang.....
Pins are now scorched, so ordered a new one to replace it as if it wasnt broken before, I am sure it will be now!
Suprisingly it doesnt look like its blown anything else either so here's hoping that everything else is still good.
Still, its going to take a little while to get the part (Ebay, China) so will advise what happens when I get and replace that part.


Here is another thought I have had (seen this method used on a dell monitor previously) - Could I disconnect the PSU component and use an external PSU wired to the right points going to the main controller board to power it instead? How do I determine what output is required and to which pins?
I see 6 pins (3 sets) coming from the yellow coil - I guess this is ground, and two independant power rails - but what voltage would they be.
Also, there is a little connector at R338 (?) that takes two pins from hot to cold side (see H01 area on pic 2 from previous posts. What does this do?

Regards
Jason

[bootlegger17]

Re: echostar hds-600

Sorry, should have read I10 on hds-600 front.jpg
Anyway see attached.

[Agent24]

Re: echostar hds-600

That's an optoisolator. It provides feedback from the power supply output back to the controller IC so it can regulate the voltage. Most likely in conjunction with the TO-92 package device next to it, which is probably a 431 voltage reference.

And of course provides isolation between the hot and cold sides of the PSU.

[bootlegger17]

Re: echostar hds-600

Going back to my previous post - anyone any ideas on how to rig up and external PSU to the right points on the MB to bypass the internal PSU?
I have determined the transformer supplying the power is from a company called longsail
http://www.longsail.com.tw/

It has the following markings on it;
SBI4.2
E150436 C (This is the part code i believe)
169747-P1
LONG SAIL 1028

I cant find much reference about it online. the homepage doesnt give that item on its parts lists, and the descriptions of other similair ones, dont give anything away as to the power outputs.

Cheers
Jason

[Agent24]

Re: echostar hds-600

A switching power supply is not like a linear one, the transformer is not the only factor in determining the output voltage - even if you found the specifications of the transformer it wouldn't help much.

AFAIK, without knowing the switching frequency, duty cycle, and probably a few other things, it would be hard to find out what voltage is supposed to come out of it, even if you did know.

Best way would be to get schematic or compare with a working unit, which is going to be hard, I suppose in your case.


Do what tom66 said, check all output diodes for shorts etc first. Check the diodes in the primary side too. If any are bad, replace them. You can test with diode test in-circuit. You should only get a reading in one direction. It looks like all the diodes in this board are marked with "CRxxx"

Might pay to check any transistors etc too.


What I would do then, If all diodes etc seem OK, once you get the new PWM IC in (and assuming nothing blows up on power on!), check for any voltage on the outputs. You can measure from the diode cathodes to cold ground. If any output shows nothing, or an output which is bouncing around, you got a problem. (Best viewed with analog meter or scope, but if you use a digital and the numbers wont stay still, it could indicate a problem)

We don't know what the voltages should be, but common voltages in these things are like 5v, 12v, 14v, 18v, 24v, 28v, 32v, from what I've seen.

[tom66]

Re: echostar hds-600

Box will use 5V and an unregulated 14~20V rail, this is standard amongst many boxes, not unique to Echostar.

The unregulated rail will be regulated down to 12V using that 4 pin regulator IC.

It may have other voltages but most set top boxes do not need more than 5V and 12V. The lower voltages always use local DC-DC converters from 5V. The 12V is usually only used by the hard disk drive, LNB power, and if present, a cooling fan. Total load, 500mA max.

The supply requirements, something like 5V @ 3A, 12V @ 0.5A.

[bootlegger17]

Re: echostar hds-600

Hi All,
referring to Agent24's last post, I have tested the CR components inline (without power) with my digital multimeter set to diode/buzz test and I get a constant buzz when I test CR58 both ways.
On CR57 and CR47 I get a short buzz and then it stops, then shows a resistance(?) reading, on both ways.
Does this mean all these 3 components are likely to be bad, or just the CR58 which does a constant buzz?

Regards
Jason

[bootlegger17]

Re: echostar hds-600

CR58 = VAN HER303
CR57 = EGP30F F AA20
I suspect its just cr58 now after a little more reading. getting no omega reading either way, or any diode volt test drop.
will try to order a new one and see what happens when replaced.
Jason

[Agent24]

Re: echostar hds-600

CR58 could well be bad if you're getting a continuity beep both ways. Disconnect one lead or remove it entirely and test again, if you still get the same reading out of circuit, it's definitely bad.

If not, check any parts in parallel with it on the board.

[bootlegger17]

Re: echostar hds-600

I should have mentioned, the last two were already removed and tested and that's the results. Only cr58 is showing short both ways. Jason

[bootlegger17]

Re: echostar hds-600

Having done a search for a VAN HER 303 I can not find the exact item.
From what I can tell a HER303 is is a 3A 200V type.
How can I find out which exact spec I need.
Looking at farnell there are many diodes that are rated at 3A 200V which is what I believe I need, but what about all the other criteria like recovery and forward voltages?

http://uk.farnell.com/jsp/search/bro...D2031%2B203047

Jason

[Agent24]

Re: echostar hds-600

http://uk.farnell.com/multicomp/uf30...1ad/dp/1861506
Cheap enough to get a bunch if you need any in the future.

The other specifications can be found in the datasheet. Google HER303 datasheet (the VAN would probably be manufacturer's name abbreviation)

I have attached both HER303 and UF3003 sheets, you can look through them and see they are practically the same. In terms of specifications for rectifier diodes, I personally go with:

1) Reverse voltage is same or higher
2) Forward current is same or higher
3) Forward voltage is the same, you can probably get away with a little lower or higher, but not too much or you might cause overheating or instability, not 100% certain so I just match it as close as I can (can someone else answer this?)
4) Recovery time is same or faster (don't know if it's possible to go too fast)
5) Junction capacitance should be roughly the same too, you might get issues if it's very different, again I am not 100% sure.

And of course, make sure it comes in a package that will physically fit on the board - or can be adapted to fit.

[bootlegger17]

Re: echostar hds-600

OK, what am I missing here?
I have received my new diodes and replaced the faulty one. System now boots.
However the HD is not spinning up. System reports fault with HD and either to Ignore, check for errors, or reformat. Tried all three options, but same results everytime.
I checked the power port for the HD on the MB and it is outputting 12v and 5v line as expected. I point to point tested the power cable with multimeter and all seems ok. I replaced the HD with another - still same results. Tried with and without the sata cable attached. Even tried alternate sata cable aswell.

Should I hear a HD spin up when just power connected? I thought so - so why am I not getting anything? Tried 3 HD's now so sure its not the HD.
Is it amps required being too much then?

Regards
Jason

[Agent24]

Re: echostar hds-600

I checked the power port for the HD on the MB and it is outputting 12v and 5v line as expected.

Should I hear a HD spin up when just power connected? I thought so - so why am I not getting anything? Tried 3 HD's now so sure its not the HD.
Is it amps required being too much then?

Did you check the 12v and 5v rails to the HDD with the HDD plugged in or not? You must check with the HDD connected to see if they are staying in spec with a load. Possibly you have bad capacitors in PSU etc and the startup current for the HDD motor is dragging the voltage down too low so the HDD can't start.

Yes, all HDD I know spin up with just power connected.

Also, did you check you have a ground connection to the HDD as well? 12v and 5v won't be much use if the ground has disconnected.

[bootlegger17]

Re: echostar hds-600

Thanks Agent24.
Yes I checked all lines, the two grounds, the 5v and the 12v. I have tested the 12v on the MB of the HD which still shows 12v.
I have placed a laptop HD inside and that powers up, as that only uses the 5v line, so defo something to do with the 12v line. Guess I need to trace the caps in the 12v line then and replace them.
I have also replaced the power rectifier on the hot side that i shorted as mentioned in a previous post. it made no difference.
thanks jason

[bootlegger17]

Re: echostar hds-600

Case closed.
Having discovered that a laptop hard drive works, and after trying to desolder two caps and struggling - i have decided to leave a laptop hard drive in.
I have placed a 1TB drive in, so should last a while
Lucikly a laptop hard drive fits just nicely on an angle with two screws holding it in underneath.
Couple of pics attached.
Thanks for all the help guys - I can recommend this gizmo for freesat - its great!

[Agent24]

Re: echostar hds-600

Yeah, those multilayer boards can be a PITA. Most STBs etc are good because the PSU (and naturally most capacitors that will fail) are on a single-sided board you can easily work on with just about any old iron.

For this kind of situation, you often need to preheat the board, have good quality tools (and flux\solder), and make sure your technique is good and efficient.

The only thing is, if it is bad capacitors, you're going to get more problems sooner or later. Good to see it working now, though!