Monday 31 October 2011

Philips 190B Fuse blown arcing buzzing faulty.

This monitor had blown the fuse in the mains lead following a sparking sound !

I stripped it down, fairly straightforward. Undo all the screws at the back, the stand screws then two longer self tappers that hold the speaker bezel and screen bezel on. Then its a case of unclipping / prizing the bezels off.

The LCD panel then unclips from the case allowing it to be tilted out. The screws holding the psu / video board cover can be removed.

I powered the board on with the covers off and was greeted with the following !






So it was fairly easy where to look next. !



A poor connection at the PCB on the live wire of the mains input was the cause. The solder hole has a heavy duty insert to prevent this kind of thing but the heat and stress must have just got worse, leading to the arcing when the track finally broke. I suspect the internal inrush limiters meant that I could repeatedly produce the arcing in the video without the fuse blowing again.


It was cleaned up and re soldered with a bridge on the track to beef everything up.



Re assembled and monitor then working fine !

Sunday 9 October 2011

HP Officejet 6500 E709a Series dead faulty PSU 0957 2271

A HP Officejet 6500 E709a printer had a dead / faulty PSU. Printer would not power on and no light on the power supply.



Opened up, nothing obvious to see. A check of all the discretes showed the diode circled was short. Out of circuit it still measured dead short.

A VSB3200 was the culprit, a 300v 2A Schotcky rectifier.

(picture shows new diode fitted and dead one out)



Tested working ok !






Thursday 6 October 2011

Nissan Navara Sat Nav bluetooth streaming (IO Play) Install

Ok, not a fix this one but when I helped a friend to do this there werent any pictures detailing the install on the web that I could see.

The factory sat nav system installed on this car (08 plate Nissan Navara) had a bluetooth function but it does not support music streaming. You would just assume that if an expensive car system has bluetooth, surely it must suport A2DP streaming / AVRCP control. I know that BMW's of the same era suffer the same problem. I suppose the standard just missed the development cycle of these systems.



So anyway, the nav system has no aux in and no cd changer simulator seems to be available (such as Dension, where you can swap the cd changer for a line in / mp3 player, I had one of these in an Alfa Romeo, worked ok). However there is still a way of avoiding a nasty FM transmitter !

Its called an IO Play, as shown here

http://www.my-io.com/en/Products/iO-Play/

Basically this unit receives the streamed music and squirts it in to the stereo system as a telephone call. I have seen some telemute kits that seemed to be a cheaper way of doing this but they all seemed to make a point they only use the front speakers ? The play outputs to all speakers.

It also takes the place of the bluetooth hands free system that is built in to the car. You can only pair your handset to one system, the IO Play comes with a mic for this.

To fit it in your Navara you will need a hands free sot lead.

This is the one we used, an InCarTec 10-556


This allows the IO Play to be installed as it comes with old fashioned head unit iso connectors on it.

The trim disassembles realy easy and only takes a few minutes, no horrible dsah out business. Just remove the cup holder first and work your way up to cd changer.

The sot connector is mounted on the back of the cd changer / brain (circled). The screw circled is a good point to mount the flying ground lead from the io play.



The next two pictures shows how the sot lead and io lead connect together.




The controller was mounted behind the gearstick, and the mic to the side. You can move the gaitor out of the way enough to pass the connectors through (be gentle though, the clips underneath are quite fragile).

There is loads of room behind the centre console for everything and the leads are nice and long. The IO boxes were placed under the cup holders.


All in. Sound quality from the music was excellent. Easy to use and the microphone placement seemed to work ok.



I would definitely recommend this system.

Wednesday 5 October 2011

Philips Streamium MCi500H/05 Dead / Faulty PSU

This Philips Straemium MCi500H was dead, no power.


NOTE !: as the messages have got quite long on this post, there is a 'Load more....' at the bottom that isnt very clear, if you cannot see your post / my reply make sure to hit this button !

Update 2019:

I am still repairing these, I would say ebay is the best way to contact me if you require a repair.

USB Repair:

I can now repair USB input problems as well, if you can no longer read from USB stick I can repair this if you remove and send me the main board.

Update: Repair service

Although I did not set up the blog post with a view to offering a repair service, there has been a lot of interest from people to get these repaired. I have successfully repaired many units, people seem to really like these and not want to throw them away.

So if you would like me to repair your Streamium MCi500H or WAC7500 please feel free to get in touch.

Update: 2018

I have continued to have good success repairing these and from other models, I have done them for people all over Europe ! The same supply is used in the WAC7500, MCi8080, MCi800, Mci900. Had quite a few now with significant failures on the switching circuit, probably switching MOSFET failure which then takes out multiple components.

So please get in touch if you would like yours repaired.

I also have a listing on eBay as another way of getting in touch. Just search on 'streamium repair'

Sound problems:

The amplifier boards in these systems are quite prone to issues too and I have repaired many of these also. If you have no sound, sound from one side, crackling from the speakers then I can repair this as well.




It was disassembled and the power supply fuse (PCB solder mount, 4A, circled in pcb pic) had blown.

The PSU was a kingwall ps131 300 e0, good old 12nc 3141 078 50341



Further fault finding showed the following components dead.

FET on heatsink
PWM IC
diode
high power resistor
bridge rectifier

All circled in this pic



no sign of any bad capacitors.

All the discretes were tested on diode check. The PWM IC was identified faulty by measuring across its rails, it was dead short.

Components changed and all running well again.



I couldnt find much on this PSU and no way to buy a repalcement, so was good to fix the original.

Blackberry Curve 9300 LCD replacement.

This phone needed a new screen, it had the lines you can see in the picture running down it. If you applied pressure to the top of the screen all the lines would disappear, I suspect it is a loose driver in the LCD assembly.



All of the ebay adverts for screens advised to remove the faulty screen first to get the part number. There are several types and a visual check is the only way to be sure.

There is a good video on youtube.

http://www.youtube.com/watch?v=6pccCCHlq94

Unclip the front panel and undo the two screws


Undo the two screws in the back, remove sim and micro sd



You have to remove the outer frame which is clipped along the sides and hooked over the top and then peel off the screen window which is stuck to the frame / screen.




So here was the screen out. Part number identified in oval,007/111 in this case. (The screen is upside shown upside down from when it is plugged in) Two circles show screws to remove screen.


A new front panel was also fitted, this is very simple and will make the phone look like new !

Replacement screen was fine.

Thursday 30 June 2011

Piaggio X9 Evolution 250 scooter incorrect mileage odometer reading

A Piaggio X9 scooter that had electrical problems after being in the rain.

Water had got into the clocks and the electrics were not happy, many dash lights randomly lit.

After drying out, the scooter was all ok except that the distance / mileage was reading 99998 km or 62498 m (bike had been set to miles but had reverted to km).







This was not good ! service history and re sale is hurt with the mileage so wrong, also it wouldnt increment ! so basically broken.

A google showed its not uncommon, water gets in at the edges of the push buttons, I found a forum post that recommended sealing the buttons and putting bags of moisture absorbing gel inside the clocks.

Surprise surprise the clocks were opened to find that the buttons had been sealed and little bags of gel put inside already by whoever had the same problem last !

The sealent had gone off / was not the correct type and had let water back in.

I also found people on the web talking about the mileage going wrong, reading 99998. I figured the mileage had got corrupted.

The mileage is stored in a serail eprom 24c02



I removed the chip and read its contents, the chip read fine and comparing the contents to a good dump I found on a greek forum, it looked valid.

This was the first thing that made me think that the chip and contents were fine, just that maybe the MCU could not read it at boot up.

Here is how I powere the clocks on the bench.



I checked that the serial eprom was powering up by checking continuity to the supply rails, they were ok.

I checked continuity of the data pin to the MCU,this was present.

I checked continuity of the serial data clock pin to the MCU and could find no connection, this did not seem right !

The data pin also connected to a large pad on the edge of the pcb, presumably for factory programming, sure enough the clock pin did not go to any of these pads, however one of the MCU pins did.

I fitted a link from the eprom clock pin to this pad and.....



Result, the correct original mileage now reading from the eprom at power on.



It looks like the link for this track in the multi layer PCB had gone.

The clocks were re sealed and re fitted to the bike, all reported to work ok, mileage reading, incrementing and storing ok.

Sunday 15 May 2011

Grundfos watermill shower pump transformer faulty. SS45DLV.

A transformer from a shower pump, no output.



Opened it up and check of the windings showed the input was open circuit. Close inspection showed a thermal fuse taped to the winding, it was open circuit.


A new fuse was selected, original was 150, replacement to hand was 135, I was confident this would be fine and the cause of the fuse going was age related fatigue and not a genuine fail. The transformer smelt fine and ran fine afterwards. The new fuse was taped back onto the windings with transformer tape.

The input selector switch routed the mains to one of three tappings. I measured the ac output at the three settings, from memory they were ~30vac, 35vac and 40vac (possibly the 45 in the model number is 45 volt max ?).

Hitachi VNR10C209 LCD backlight inverter faulty.

A faulty backlight in an industrial lcd touchscreen.

The inverter board was a seperate PCB, a quick check of the thermal fuses showed that one had gone. A nice easy fix but not an immediately obvious one, I had not seen an inverter with this protection before.

In the picture you can see the top fuse I had replaced and the bottom one is the factory fit.



Both replaced, the lower one is not bonded to the transistor yet.


I stuck them down with silicon sealant (weighted down until set), fine at these temperatures.

The fuses were 115 degrees. On soak test the chips it was bonded to never got above 40 degrees so I am putting this one down to age fatigue on the thermal fuse, not uncommon in my experiance.

Saturday 30 April 2011

Alinco DJ-193 no sound from internal speaker.

An Alinco DJ-193 where the built in speaker no longer worked, headphones worked fine.




Opnening was fairly straigtforward, (after finding nothing on the web).
Remove the antenna and pull of the rotary knob.

Then just flex the sides at the points shown to disengage the metal tabs from slots in the case and tilt the whole metal lump out.



A nice straightforward one, the fault was clear to see immediately, the speaker wire had at some point been pinched between the case and the metal assembly and been cut clean off. It had never been opened before so presumable from assembly at manufacture or the wire had moved through use ?



The wire was re attached and the speaker worked again.

Sunday 24 April 2011

LG 32LX2R Faulty power supply.

A LG 32" LCD TV that would not power on, the fault occurred following a mains power outage.

The PSU board looked fine, no bulging or stained capacitors. Aquick google went straight to the point, somebody with identical experiences who recommended changing the output stage capacitors (circled) anyway.

http://forums.moneysavingexpert.com/showthread.php?p=27092505

post number #31



The capacitors were sourced, 14 in all. The board was of reasonable quality, no problems removing the old ones.

Here is a close up, all the old capacitors looking ok


So in went the caps. I measured all the old capacitors and they were all in spec for capacity on a basic Fluke multimeter....

However the TV now worked. I would be interested to know the failure mechanism of the capacitors but a good result and Google delivered as the capacitors really dint look suspicious.

Update:

Here is the capacitor list:

2200uf 10v x 1
1000uf 35v x 4
1000uf 25v x 2
1000uf 10v x 3
680uf   25v  x 2
100uf   50v  x 2

Update:

The likely failure for the capacitors is poor ESR, (equivelant series resistance) at given frequencies. I have access to a proper LCR bridge. A quick measure shows ESR varies with physical size on new capacitors, I will need to look into specs for given values and see if there is a large deviation from spec.

Update:

Ok, I had kept the capacitors and measured them all. Here is a table of typical ESR values. This is from a manual of an ESR meter made by Peak electronics. I hope they dont mind me using it, here is a link to there meter http://www.peakelec.co.uk/acatalog/jz_esr60.html

There are three 10v 1000uf capacitors in the TV PSU, two measured just under 0.2ohms but one measured 2.1 ohms, so it looks like this was the likely culprit.

The esr meter above can be used in circuit, I hope to try one out soon !

Monday 11 April 2011

Dell 1708fp ultrasharp backlight fault

A dell 1708 monitor, the monitor would power on, screen would display for two seconds then the backlight would go off. You could faintly still see the graphics in the background.

This was exactly the same as the Samsung 540n I fixed in an earlier post, that was bad PSU caps so I was expecting to see similar inside.

Disassembly was straightforward. Four screws in the middle of the back,( behind the stand bracket), then unclip the bezel all the way around (this was tight !). Pull the back off, remove two screws from each side to release the electronics assembly from the panel, remove back-light wiring covers then cables, remove main screen cable. Finally to get to the component side of the board, remove output connector locking screw posts then screws from the back of the PCB.

I wasn't disappointed, more bulging brown stained caps than you could shake a stick at, six in all, all clearly failed.


They should be 35v 330uf, removed they were measuring about 150uf.


Here they are in all their glory.


New caps in, I have circled the six affected capacitors that were replaced.



Back together with the new caps, all working ok !


Tuesday 5 April 2011

Hauppauge HD PVR wrong power supply.

A Hauppauge HD PVR that had been powered up using the wrong PSU.

With the correct PSU used again the unit would not work.

Unfortunately I didnt take any pics so I used one off the web to describe what I found, I hope the owner of this picture doesn't mind, it was from a blog post about modifying a unit by fitting a fan.

http://blog.arogan.com/2008/06/hauppauge-hd-pvr-model-1212.html



The picture does however raise an interesting question as it differs slightly, voltage regulator 4 was not present in this faulty unit ??

A good chunk of the circuit runs off 3.3v as you would expect, this seemed to be handled by the regulator #3 derived from the incoming 5v.

However some of the circuit runs off the 5v input straight frsom the wall adaptor, no circuit mount regulation or fuse.

Plug in the wrong supply and....

Pooof, at the very least IC's #1 and #2 were toast, #1 was long gone, nothing at all left of it. #2 was still present (a FMS6403 component video driver) but there was a hole in it.

I didnt spend any longer on the unit and told the owner the bad news, mostly as I could see no easy way to procure a FMS6403 and not knowing what chip #1 was. Chip #1 looked like it was a 3 terminal chip (Vin ground, Vout), there may have been some way to hack arround this.

Im sure some circuit protection would not be too expensive to design in. Hauppauge's idea of protection is a sticker on the back saying 'only use the supplied PSU' well, obvious but accidents do happen, searching the web showed that plugging the wrong PSU in was not an uncommon occurrence.

Saturday 19 March 2011

embedded PC Broken USB ports

This was a batch of embedded PC's with broken USB ports. Rough treatment had seen the supports snap off making the whole thing very wobbly.


The only key here is heat, lots of it.

This isn't the most interesting fix but its worth dwelling on some of the fundamentals of this kind of repair.

1. Patience, never rush the de solder, pulling on the component while applying the heat could have disastrous effects, pulling out the through holes or lifting the track.

2.Choose the right weapon, see that big ground plane there ! and what about the multi layers, thats going to take a lot of heat, if your iron cant cope it will never realy get hot enough and ..... see point 1 ! Experience has taught me you should only attempt the de solder if you have the right iron to hand.

I solder sucked the middle four pins and used a HUGE iron to get the four outer pins molten and pulled it, solder braid or solder sucking would just not get the holes clear so pulling was the only option, now I have just warned against pulling but you just have to get a feel for it and hold back until its hot enough.

On this board you can see the four mounting posts have all snapped off, this actually made the de solder easier as that metal shell would have pulled a lot of heat away. In fact I had another (I should have taken more pics) where the shell was fine (contacts inside had been mangled) but I purposely broke the four tags before attempting the de solder.

For this one I hadn't got the spare connectors yet (the connector was fine, just the mounting tabs were faulty) so improvised by making straps out of tinned copper wire and re used it.


A nice fix but for the others I used brand new connectors, only about £1 each.

The PC's were AMD Geode based which I had not come across before. They are AMD's competitor to Intel Atom.

Asus Eee PC noisy fan.

Not a lot to this one as I unfortunately didnt take any pictures of the interesting bit.

An Asus Eee PC 1000HD had an intermittently noisy fan. The case came apart fairly easily, starting with keyboard removal, there are sprung loaded tabs along the top row of keys and some tabs that you push on the underside.

You then need to remove all underside screws to release the heatsink plate / top shell.

Here is a pic of it at that stage, you can see the fan on the left, it is between the bottom shell and the mainboard.


Finally remove the screws in the screen hinges / remove all cables to allow the mainboard to be moved clear of the bottom shell, the fan can them be removed.

On the bench the fan was running fine but the fault was intermittent.

Here is a library picture of the fan

The metal plate was removed by taking out the three screws, what was evident was that the fan blades had been rubbing on the metal plate and scored a groove in it, its possible this was creating the noise.

The blades lift off , the shaft is located in a brass bushing, wear of this part may have caused the rubbing. The bushing was lubricated and the plate re fitted with washers spacing it slightly away from the blades to prevent rubbing.

We will see if this gives it a new lease of life, I will report back how it runs in the long term. A new fan is not so much £10, if I had known before I was asked to look I think I would have just told them to get one to replace.

Saturday 12 March 2011

Stanton C.314 faulty LCD display.

The fault with this Stanton CD Deck was that not all of the display was working. The unit itself functioned ok but just having part of the display working was very distracting as you couldnt see where in the track you were etc. in the pic the sub digit of the pitch setting in the top left is totally missing.




A search on the web showed a lot of people complaining about reliability of these units. This in turn seems to hurt used values.

Having had one in bits Im undecided, they are not bomb proof for sure but they arent priced at the top end of the market either, however Im sure a DJ deck will see a pretty hard life regardless.

There was a lot of talk on the web about an under specified capacitor on the power supply causing trouble, rebooting, not powering on etc, both the units I have seen had factory fitted (you could tell buy the bonding to the board) uprated 10,000uf caps (earlier units got a 6,800uf). These with the 10,000uf were dated July 2007 and Sep 2007.

So just a few segments not working, I checked for bad soldered joints and everything seemed ok. Also after some time and under close scrutiny the segments that were not lit did actually look like they were trying to be driven, at the right angle you could see that some were being driven / changing state, just very faint, some were totally absent though.

I took the LCD substrate off the PCB with a view to driving individual segments, what I found was that with just the charge on your fingers (or with a meter on diode check) by touching the pins in certain ways you could make segments switch state, including the ones that wouldn't work when connected !! ??



This made me think the driver chip was at fault.

I looked at the data sheet for the LCD driver a sitronix st7066u

http://www.sitronix.com.tw/sitronix/product.nsf/Doc/ST7066U

http://www.sitronix.com.tw/sitronix/SASpecDoc.nsf/FileDownload/ST7066U614654/$FILE/ST7066Uv22.pdf


and started poking arround with a scope to try and determine if an output was at fault, they all seemed to be the same though. My main focus was arround the pitch digits on the display that were not lit as moving the pich slider should have had this digit (seven segments) changing , I found the exact pins responsible for driving these segments (by looking on the scope while moving the slider) and they seemed to change state correctly. I then wired the driver chip outputs for these pins to other different pins of the display. Sure enough moving the pitch slider made the other segments change state, so it must be the LCD itself.

It was interesting to read up on how the LCD worked, duty cycle and voltage levels that multiplex the segments (the data sheet explains more), it wasnt something I had not dealt with down to this level.

Whilst I was probing arround the LCD driver chip I found that if you grounded an output, the chip went into a fault state where it would illuminate every segment of the display and in this state the faulty segments still did not change state.



Sooo.... I needed a new display

Stanton UK service centre wanted £200+vat for a full top board. Oh dear.

A second call asking if they could 'find' me a scrap one led to an offer of a scrap top board for £50 delivered, a generous offer to be fair but not realy the ballpark I was working in based on the used value of the unit.

A lot of calling round independant DJ service people was a mixture of no chance or hopes being raised then dashed, only one guy was rude to me, mostly very helpful.

Finaly Steve at www.trusound.co.uk he sold me a scrap unit including LCD for £30 delivered, great guy to deal with and he saved the day.

Here is the donar, all segments working, interesting to see the amber display on the lower specified unit :-)
(error is due to the fact this unit had no CD drive fitted).



So LCD swapped over it was time to see !....



Nice, all working.