Cant get my blue ray working because of amp. Anyone ? [Archive]

alexk0il

29-04-2018, 23:38

Edit: following the recommendations from snowman I isolated the issue to be more likely with the AMP, not with the BR. subject changed.

See the update: http://theartofsound.net/forum/showthread.php?58174-Can-t-get-my-Blu-ray-working-Anyone&p=973561#post973561

~~~~~Original Post~~~~~~~~~~~
Hi,

I’m unable to connect my new Blu-ray UBP-X800 player to the existing audio/computer setup. My main power circuit breaker kicks in and jumps the fuses when I use both HDMI and digital audio coax of the Sony. Here is a brief description of my setup, please see the diagram below.

I have a good sounding combo of a DAC plus a 40-year-old 2x70W integrated amp/receiver. The amp has a two pin EU power plug, no grounding.

The Blu-ray has the normal three pin UK connector, however the ground pin is plastic and is not connected to anything. The LCD screen is the only device that has a three pin power lead with the actual ground pin connected, so I guess that’s the only ground in my system.

If I disconnect the digital coax from the DAC, Blu ray plays fine on the LCD.
If I disconnect the HDMI from the LCD, Blu ray makes an amazing sound through the DAC + AMP (I obviously need to power up the DAC)
If I have both HDMI and the coax SPDIF connected to the DAC and LCD, then turning on the AMP activates the power circuit breaker.

This happens even when the DAC is not connected to power (see the diagram) and even when both the LCD and blu-ray are not turned on. As long as the LCD and Blu-ray are connected to the power the problem exists.
Disconnecting the Gnd wire between the DAC and Amp doesn’t change a thing
I suspected power spikes when the Amp is turned on, so I tried to turn it on without the coax cable to the DAC and to connect the coax cable when the Amp is alive (the amp is designed to make this old-fashioned click before it can play anything). Connecting the digital coax after the click makes sparkles and brings the circuit down.

Since both video and audio parts of this system work fine when they are not used together, I am not 100% sure if I can blame the Blue-ray and I am not missing something obvious here. Do you think this problem can be explained by bad cables, amp or DAC hidden problems or design issues or may be by something else?

Thanks

23428

Mixc

30-04-2018, 04:44

Hi , Are they all plugged into the same mains extension lead or are the on different ones?

snowman_al

30-04-2018, 07:09

Umm, I would be more than a little concerned here. Earth leak trips and 'sparkles'... Please BE CAREFUL until you know what the problem is. Do not touch any exposed metal parts, cases, connectors etc. with the mains power on.

The only Mains Earthed component on your system is the LCD. When you connect the HDMI just to the blue ray, the blue ray becomes earthed too. So I would assume the player is OK.

Then when you connect the blue ray coax to the DAC you earth the DAC and amplifier too. (The earth comes through the screen wire of the HDMI, coax AND signal cables.) So it could be either the DAC or amp at fault.

Next you say it happens with the DAC disconnected from the mains. And if you remove the ground wire between the DAC and amp. But unless you remove the signal wires too (L/R Line in) the earth still goes to the amp via the screen of the signal cables.

Next step is to remove the ground and signal wires from the amplifier. If that is OK, power the DAC up too (still with no connections to the amp) and see.

If that is OK then either the amp is causing the problem or very unlikely the LCD. Remember unplug everything before touching the connectors or cases!

struth

30-04-2018, 07:50

Sounds like one is at half mains potential compared to other at either end of cable. Can happen when you have things like a tv that's on say a 2 pin smps and an earthed component. Probably lowish current in micro Amps but get it checked. Also your earth leak trip could be sensitive.
Get it all checked by a competent technician

alexk0il

01-05-2018, 09:41

Hi , Are they all plugged into the same mains extension lead or are the on different ones?

All is plugged to the same extension lead except for the BR, see the diagram attached in OP.

alexk0il

01-05-2018, 10:38

Umm, I would be more than a little concerned here. Earth leak trips and 'sparkles'... Please BE CAREFUL until you know what the problem is. Do not touch any exposed metal parts, cases, connectors etc. with the mains power on.
...
Next step is to remove the ground and signal wires from the amplifier. If that is OK, power the DAC up too (still with no connections to the amp) and see.

If that is OK then either the amp is causing the problem or very unlikely the LCD. Remember unplug everything before touching the connectors or cases!

Thank you, Snowman, your recommendation to check ground issues by attaching devices one by one does make a lot of sense and I guess comes from experience ;).

The DAC (also powered by a two pin power source) works fine in this setup, which suggests that either LCD or the AMP is to blame. Just to confirm my findings I connected the HDMI ground from the LCD to the Gnd on my AMP. This takes the BR and the DAC out of the equation.

Yep, it surely does break the circuit when the AMP is powered on. To be on a safe side I used a single tiny OFC wire thread from my multi-core speakers cable and it gave me a nice puff with small yet beautiful sparkles before the wire thread evaporated and the main circuit breaker took over.

This is quite strange as the AMP has only two pins and I would expect it to float with any ground as long as it is common to all equipment. Considering the sparkles I am now more concerned with not getting myself or my kids accidentally fried if a ground signal somehow comes close to the AMP (unattended HDMI cable, another device with 3 pins plugs nearby, etc.)

I will try to connect the AMP's directly to the ground pin of the wall socket to completely exclude LCD, but I don't have a spare 3 pin plug to play with, so it will take time.

Anyway, I think I agree it is very unlikely to blame the LCD, so I am checking the AMP schematics to see what's going on. I can't figure out if this is due to incompatibilities between different variants of power supply unit with UK power sockets or is it because it is faulty indeed. Mine is the Asia/Latin America variant and it does not have the ground in the PSU board (page 14 of the service manual in the link). The last time I looked at something similar was 30 years ago though, so going through the schematics takes a bit of time for me :). Just out of curiosity, is the UK main break circuit supposed to kick in when Ground touches the Neutral wire?

https://www.hifiengine.com/hfe_downloads/index.php?hitachi/hitachi_sr-604_service_en_de_fr.pdf

Thanks a lot.

snowman_al

02-05-2018, 08:56

OK a few things to think about.

A warning again. Do Not touch any metal or conductive parts of the Amplifier or LCD when they are plugged in until you know it is safe or repaired.

First - If you have a multi meter, check to make sure your mains socket is wired correctly. First at the wall socket then at the extension sockets. Test between Live and Earth first, then Live to Neural. (These should be 240 volts ac and very similar.) Then Neutral to Earth. If you measure a large voltage Neutral to Earth (or have a large difference between L - E and L - N readings) there is something wrong with your mains.

Prove the LCD is not to blame. - If you have a multi meter, ensure the HDMI metal connector is connected to the mains earth pin on the plug. Use lowest ohms range and it should be less than 0.5 ohms. (Alternatively, but not recommended, plug the HDMI lead into the LCD and hold the metal part of the other end of the connector to a known good earth, metal radiator or mains socket screw head etc., and then plug in and switch the LCD on. If it trips the breaker the LCD is faulty.) As before DO NOT touch any metal parts until you know it is safe.

The amplifier. - Again if you have a multi meter, use the 20K ohms range to measure from the Ground connector on its case first to the live and then neutral pins on the plug. Obviously not connected to the mains. Now if you press the amplifier mains switch on and have a reading of less than 20K ohms on either or both there is something wrong inside the amp. (The alternative is as before, but you must use thick and well insulated wire if you do.)

I cannot see the diagram you link to so do not know what amp you have still. Best guess / hope is there is an arc suppression network or capacitor across the mains inside the amp that has gone very leaky electrically. But it could be anything - a faulty transformer, an electrolytic capacitor has oozed some 'goop' across a mains voltage connection or failing circuit board...

An RCD breaker normally responds to a fault across the Live to Earth path. Neutral should be at or near the same potential as the mains Earth, so normally should not drop the trip. If it does do get the mains checked.

Again, Please Be Careful. Any doubt get a qualified person to sort it.

alexk0il

03-05-2018, 19:15

Thanks a lot. This is amazingly helpful and I am learning quite a lot during the process. As an engineer I do appreciate the way you think and isolate issues one from another.

Voltage between Neutral and Live in mains is ~1.5-1.9V AC (and a few mV DC). The rest seems to be normal.
LCD seems to be fine
Amp - something is going on

Switched off - everything is in mega-ohms.
Switched on

Case Gnd to Earth pin ~0.5 MOhms
Case Gnd to Neutral or to Live ~10 Ohms, definitely wrong.
Neutral to Live measures ~5-6 Ohm

Additionally, case Gnd to Earth on HDMI lead gives 83-85V AC at ~0.2kHz.

Anyway, I got this AMP for an exercise on how to recap and to regulate it, but because it sounded so good I did not rush to open it up and to risk killing it during the exercise. I guess there is a now a good reason to do it sooner rather than later. The amp goes off the mains till this is sorted out.

Do you have any other tips that can help to save time in chasing the problem? I hope it's just a broken wire touching something it's not supposed to, but can't tell without opening the beast up.

Anyway, I know I'm pushing your patience, but just in case, here is the link to the amp service manual :D

https://goo.gl/FzJ83i

snowman_al

04-05-2018, 09:38

Not a problem.

I assume your statement, ''1. Voltage between Neutral and Live in mains is ~1.5-1.9V AC (and a few mV DC).'' is a typo and should be Neutral and Earth? If so that is fine.

At least you know the amplifier is faulty. Lucky you found it before there was an injury... And I can see the diagram too now.

''- Neutral to Live measures ~5-6 Ohm'', this is fine too and normal for the primary of this type/rating of transformer.
''- Case Gnd to Neutral or to Live ~10 Ohms, definitely wrong.'', definitely!

When you get the lid off follow the mains lead wiring and look for the obvious failed component, a loose or shorted wire, extra screw lodged between tracks, etc.
Then the mains switch for signs of 'tracking' (burn marks or cracks that carbonise and become conductive over time).
Same again at the part for Latin America marked Audio P.W.B(3). Top-ish right hand side on page 14.

Test the mains transformer next. You need to check A there is no connection between the primary mains winding and either of the two power supply secondary windings. And B that the primary mains winding is not shorted to the metal core of the transformer.

Unfortunately the only way is to disconnect all the transformer secondary connections, marked 21, 22, 23, 24, 26, 28 and 29, on the diagram, from the 'Audio P.W.B(1)'. Leave the primary ones 9, 6, 4, 3, 1 and 2 connected.
Put your meter on the 1Meg ohm range and measure between 21 (power supply secondary) and 9 (mains primary) for example. It should read open circuit. And for the other secondary from 28 to 9 again should be open circuit. Anything other than very high resistance here is a transformer failure.

To check for a short to the core do the same test, but put one lead on the case Earth terminal and the other on 9 (mains primary). It should be open circuit too.
Again, anything other than very high resistance here is a transformer failure.

It takes longer to write it than do it, so good luck!

alexk0il

05-05-2018, 11:56

Thanks. I am definitely lucky to catch this before an accident. Tuning the amp involves sticking hands inside and turning potentiometers on a live amp.

I have family staying with me, plus I want to solder/desolder components on a junk electronic board before I gain confidence with my soldering skills. I guess I will be come back with meaningful results in a couple of week.

I will keep you updated .

Thank you again,
Alex

alexk0il

10-05-2018, 15:12

Four hours with screwdrivers, wrenches, one Styrol cap on AM/FM receiver board is accidentally broken, but I still don't have access to the main board or to the transformer. :eyebrows:

Oh dear, these vintage amps were supposed to outlive the human race after a nuclear war.

snowman_al

10-05-2018, 15:19

''Oh dear, these vintage amps were supposed to outlive the human race after a nuclear war.'' - Sorry, no only the valve ones survive the atomic pulse!

It's all part of the fun...

Posting a picture(s) might help. There is little on the web to look at with respect to your version.

alexk0il

10-05-2018, 15:56

''Oh dear, these vintage amps were supposed to outlive the human race after a nuclear war.'' - Sorry, no only the valve ones survive the atomic pulse!

Thought he capacitors might leak before the nuclear war though... But mechanically wise it will be intact. :D

Posting a picture(s) might help. There is little on the web to look at with respect to your version.

All my photos are related to cages, covers and to the web of connectors that hold everything intact. I am sure I will fully enjoy working on glued three legged capacitors, I guess I will have to break them before de-soldering. But I might be "lucky" to discover the broken unobtanium transformer which I suspect can justify binning the amp and saving the pain ;)

Anyway, I only took photos of the screws and connectors, not sure if these are interesting to anyone. Here are the photos of my and a very similar SR-2010 amp (it has one extra capacitor in the PSU and bigger/better heat sinks) from a German forum.
https://translate.google.com/translate?sl=auto&tl=en&js=y&prev=_t&hl=en&ie=UTF-8&u=http%3A%2F%2Fwww.hifi-forum.de%2Fviewthread-185-12766.html

snowman_al

10-05-2018, 18:06

Umm, I see the problem.
The primary windings are on top and the secondaries are hidden away down below. And no real markings to identify the numbers from the diagram, doh.

If yours is the same configuration as the pictures then it might be easier to remove the primary winding wires instead. And leave the secondaries in place.
Could you un-solder the 6/7 wires from the top of the transformer? Brown (9) white, red/red, blue, yellow and black (2). Make sure you note the positions very carefully before you start.

Then do the resistance test between pin 9 (Where the brown wire comes from) and any of the secondary terminals 21 to 26, and again from 9 to either 28 or 29 the bulb winding. Now go from pin 6 (where the red wires were) to any of the secondaries 21 and 26 and then 28 or 29 again. (As there are 2 primary windings so you have to test them both...) Then the short to core test as previously described.

Hope the colours and locations on yours are the same as the pictures.

Fix this before worrying about the caps ehy?

alexk0il

17-05-2018, 22:53

Finally found time to work on this... A bit of unsoldering, a bit of unscrewing and I managed to remove most of the front panel and the back sides of the case. I'm still puzzled though the back panel, can't figure out how to undo a couple of connectors before removing the back panel.

Anyway I followed your advice and tested the transformer with primary winding unsoldered:

Both 6 and 9 give infinity readings to all secondary terminals.
Gnd to 6 or to 9 - infinity
Gnd to 28, 29 - infinity
Gnd to all terminals form 21 to 26 - shirt circuit. :stalks:

Don;t understand the last measurement. Perhaps I damaged something on electronic boards during the disassembly. :doh:

snowman_al

18-05-2018, 06:43

All those readings look good.

- Both 6 and 9 give infinity readings to all secondary terminals. = No primary to secondaries short.
- Gnd to 6 or to 9 - infinity = No primary short to ground.
- Gnd to 28, 29 - infinity = No 'bulb' winding short to ground.
- Gnd to all terminals form 21 to 26 - short circuit. = This is correct. Pin 23 is connected to the ground terminal and effectively 'ground' 21 to 26 due to the low resistance of the winding.

It almost proves the transformer is OK. Almost, because it may only breakdown at mains voltage. The voltage used by your meter will only be 9 volts max.

Next eliminate the wires from the mains to the transformer. Meg ohm resistance check again, case ground to each of the wires you removed from the transformer. Make sure to test with the power switch off and on.

alexk0il

19-05-2018, 13:19

power switch off and off: gnd to all removed wires shows open circuit

I'm confused... Since there are no issues with the transformer and with the unsoldered wires does it mean that the problem is gone? I don't think the 9V of the meter can be blamed, I could see the 6Ohm between Gnd and the other check points using the same multimeter.

May be Gnd is not supposed to be connected to terminals 21-26 and the problem is still there. I can't actually trace in the schematics how the gnd is connected to 21-26. Some diagrams show it is connected on a US variant and not on Asian and Latin American.

Another explanation is that I removed the case, front panel and had to disconnect a few wires between the front panel, main audio board and front-panel LED board. Perhaps this explains the good reading on my meter...

snowman_al

19-05-2018, 16:30

''I'm confused...'', me too, but that is how these faults go sometimes.
So far you've proved there is nothing obviously wrong! Maybe there was a blob of solder or strand of wire in there that has now fallen out? 50/50 chance I guess.

I think the case or chassis Ground comes from pin G1 (top left on the Tuner PWB)?

Image removed no longer needed.

It is tricky to follow, but it does eventually end up back at pin 34 on the Audio PWB and that is wired to number 23 (the low voltage centre tap) on the transformer. It is difficult to trace these without the boards in front of you. But you should be able to follow it through the circuit boards with your meter.

''I don't think the 9V of the meter can be blamed'', no the meter is fine. The problem is a 9 volt meter does not put any stress on a 'leak' between two windings or wires if they only 'break down' at mains voltage.

Without knowing exactly how far you have it apart, it is difficult to advise what to do next apart from putting it back together temporarily and trying it again.

I would strongly suggest that you fit a proper mains earth wire, at least as thick as the live and neutral wires, from the case ground terminal to the mains plug earth pin, before any further full voltage tests. If you look at the diagram again you will see the European version with the 3 core mains lead connects the earth to the chassis (the little brush symbol).

alexk0il

19-05-2018, 18:57

Thanks, I managed to find other connectors to Gnd close to speakers, and somewhere in the middle of the board and missed the G1 :)

I'm not saying the meter is not fine, i'm just saying that since we did see the problem with the meter, I would expect the same problem to show up after desoldering. Whatever it was the meter was fine to pick it up.

I will try to find the way to attach the earth wire when I am done, though the Asian/Latin american power board might be different and not have the connectivity to the grround. I will simply attach a proper lead to one of other Gnd terminals (Green wire on the LED PCB board on my photos).

I think I will try to reconnect all desoldered wires back to confirm that the problem has gone and then i will proceed with recapping.

Here is where I am currently stuck. i am still struggling to remove the back-panel. Will show in the next post what i stopping me.

alexk0il

19-05-2018, 18:59

I can't figure out my way around antenna's connectors. How do i remove them?
23553
23554

alexk0il

19-05-2018, 19:01

Also power leads/connectors
23555
23556

I might be able to unclip the unswitched connector, pull it out and desolder the wires, but how do i detach the main lead cable/connector?

snowman_al

20-05-2018, 07:18

Yes that is not the easiest to work on.

''I will try to reconnect all de-soldered wires back to confirm that the problem has gone''. -- That's the plan!

''I will try to find the way to attach the earth wire when I am done'', -- Please fit the earth lead before you plug it in again.
''the Asian/Latin american power board might be different and not have the connectivity to the ground. I will simply attach a proper lead to one of other Gnd terminals (Green wire on the LED PCB board on my photos).'' -- I would not.
-- The Very Best place to fit the earth lead to is the back of the GND terminal (it shows in your second lot of pictures). That way the case and chassis are always protected. (Using a point that includes a PWB track or thinner wire could result in it acting like a fuse in a fault condition and that would leave the case and chassis being Not Protected.)
There are a couple of useful things to read here about Earth Safety. http://sound.whsites.net/psu-wiring.htm sections 2.2 and 7. And http://sound.whsites.net/earthing.htm

TBC.

snowman_al

20-05-2018, 08:59

Question is do you need to take it apart any more?

Right now you just want to prove it works OK, so put it back together as much as is necessary.
To make it safe to test, without replacing the mains lead right away, add an external earth wire from the plug to the GND terminal on the case. Just make sure it is a good connection.

Then when you know it is working fit a 3 core mains lead. I expect removing the mains transformer will get you more room to do that?

To get the aerial connections off you need to unsolder the 2 wires from the case and then the 3 terminal lugs from underneath.

Again are there any caps you cannot get to without taking it all apart?

alexk0il

17-06-2018, 16:20

Hi Alan,

Finally got the job done, though I killed the FM receiver in the process and got a really nasty burn on one of my fingers from the soldering iron:

grounding problem - fixed
power supply capacitors - recapped
bias - adjusted

We couldn't see it on a half disassembled amp because it only appeared when the heat sink panels were properly screwed to the chassis. It took me a while to find that it was related to the heat-sinks, but once I found it the rest was easy. The amp has a special jumper board attached to the heat sink, to switch between 220V and 240V. The person that screwed this jumper board was an imbecile, the 220V side was pressed so hard to the grounded heat-sink panels that the jumper board was bent. The 240V had a nice 3-5mm of clearance as it should. This would not be a problem, unfortunately two other factors kicked in:

The jumper was set at 220V instead of 240V, which contributed to overheating
Both bias regulating potentiometers were set exactly in the middle of their range, i.e. not regulated. The readings at test points gave 150mV/190mV for L/R channels instead of the required 8mV; another factor co contribute to the overheating

My guess, after years of running at extreme temperatures the insulation of the jumper board gave up. There were only ~3-5 Ohms resistance left between that wire and the Ground at that point. Not nice!

To fix it, I moved the jumper to 240V, plus squeezed a peace cut from my old driving license between the 220V point and the heat dissipating panel. I also readjusted the bias to 8mV, so no more overheating. See the attached image.
23704

The sound coming from this amp is now amazing - full, vivid, rich, detailed, dynamic, the humming and noise completely eliminated, and it is still getting better and better every day. It's headphones output is also so much better than of my Beresford BM, which I thought to be the pinnacle of the sound clarity and details, that I completely stopped listening to my headphones through the BM, only thorough the amp now.

Anyway, thank you for your guidance and help. I would have never made it without your support, and who knows, I could have been electrocuted due to the ground issue if I tried to work on the amp before fixing it. The beers are on me if you get to Marlow/Maidenhead area.

snowman_al

17-06-2018, 17:42

Well done Alex. Not a problem to help and I'm glad it is working safely. I wondered if it was in the skip by now ;-)

I can now see what the problem is from your latest picture...
You are correct, whoever assembled the voltage selector tag strip was a complete (expletive) twonk.

You MUST turn it trough 90 degrees and use the two vacant holes in the tag to mount it. You will have the correct clearance (loads) between the high voltage connections and the heat sink. And get your licence back!

Go and do it now ehy! Alan

alexk0il

17-06-2018, 18:17

Hi Alan,

Thanks for the tip, I see what you mean by 90 degrees, makes perfect sense.

Unfortunately I can't do it. The screws got "welded" or corroded into the mount and I don't have either a good clearance (can;t take the back panel off, remember :lol: ) and can't apply enough pressure to unscrew them without stripping the head off. I will check periodically if it is ok, may be will add insulating pads at 240V side as well. Or may be I will get a wrench that can work at 90 degrees, though I am still not sure if unscrewing it is still feasible. That little screw on the left (it is actually twice shorter than on the right) does not want to move.

Cheers
Alex