The Professional Repair Services Logo featuring a printed circuit board mask

email repair@prscardiff.co.uk
telephone (029) 20 664 163
mobile 07906 550 363

Professional Repair Services Ltd
78 Richard Street, Cathays, Cardiff CF24 4DD

News

IT services for Modus Consulting

26th February 2010
I haven't documented any of the IT services provided to companies in the news section, but will do so from now on. Setup of print server, general maintenance and cleanup to restore speed to PCs, RAM upgrades and workstation preparation for new employees were completed today. A broken windows install was repaired so that networking functions worked properly and an emergency safety backup of company data was made due to warnings signs of possible disk failure in a vital file server. The warning events turned out to be spurious during investigation after the data had been backed up as quickly as possible - any signs of disk failure are not to be taken lightly!

Allen and Heath Xone 42 mixer

25th February 2010
This mixer had liquid spilled into it at a party. The mixer was immediately turned off and left to dry out - a good decision by the owner. Upon switch on, only half the lights came on and there was no sound. Upon dismantling the mixer, the power and sound backplane was discovered to have corrosion and leaching damage which was cleaned up and repaired. The power supply was checked and was ok. Power was still missing so a further investigation of the pcb tracks with a multimeter showed an open track and 'via' that did not appear visibly damaged. Repairing the track brought the mixer back to life.

Samsung 913N LCD monitor

24th February 2010
The monitor displayed 'Not optimum mode' and refused to display a picture even if the right mode was selected. This was due to a failed controller chip. A mod was done in an attempt to bring it back to life which partially worked - but after some time on heat build up in the case and the associated increase in temperature of the chip cause the fault to return. Some heat-sinking was attached to the chip which seems to have cured the fault.

Philips 1200 series laptop

19th February 2010
Internet Explorer was acting up and laptop was slow. Cause was a trojan horse and spyware.

Advent 5301 laptop

19th February 2010
Laptop was overheating and was unstable. Cause was dust build-up in cooling assembly.

Fender Twin Reverb valve guitar amplifier

17th February 2010
Well this was interesting, a really old valve guitar amplifier - late sixties early seventies vintage. Very poor physical condition and electrical condition, broken reverb, very low distorted output. The low and distorted output was cured with a set of replacement output valves and the dead reverb was caused by a fried output transformer that drives the reverb tank. The secondary had shorted and led to the failure of the primary high impedance winding. The transformer had to be shipped from America and thankfully repaired the amplifier to good working order - very loud and really nice sounding reverb.

Boss ME-50 guitar effects pedal unit

16th February 2010
The power jack was intermittent as well as the headphones jack. Somewhat annoyingly to repair them meant having to dismantle the entire unit to get at them. The fault in both was not the socket or the soldering, but failure of the PCB tracks around the solder. The effects unit was restored to good working order.

Denon DN-S5000 CD deck

10th February 2010
The deck had a faulty pitch control which had gone non-linear due to a spilled drink. The control was removed, dismantled, thoroughly cleaned and lubricated. This returned the deck to good working order.

Apple Powerbook G4 Aluminium laptop

27th January 2010
So many problems, don't believe the Apple hype :(
1. Stuck battery, release mechanism broken. 2. Power adaptor jack worn out and cable split and shorting. 3. Power socket intermittent and broken. 4. Battery worn out. 5. Laptop hinge loose. 6. Broken screen clasp. 7. Damage from dropping.
Started by repairing the power jack which was obviously shorting by the sparks coming off it when the cable was flexed. Repaired the plug nicely by dismantling and resoldering with some unbroken flex and fixing with resin. Then discovered that the power socket was broken too. To dismantle the laptop the battery needs to be removed which was stuck. Took about 2 hours of gentle levering and playing with the release control to free it. Finally got cover off laptop, discovered that everything needs to be dismantled to get at the board with the power socket on. Everything! Removed motherboard, hard disk, cdrom, speakers, pcmcia slot mechanism. Removed power board, removed socket and installed heavy duty power socket. Snipped off nicely repaired power jack plug and put on a standard power plug and fixed insides with resin. Repaired battery release mechanism. Reinstalled pcmcia socket, speakers, motherboard with new thermal compound, cdrom and hard disk. Dismantled screen to investigate loose hinge, which was really quite frustrating to do. Repaired screen latch. Discovered that the loose screws were not easily accessible without dismantling the screen itself further, which I decided against due to the possibility of damage to the screen. Why design like this? Absolute madness! Reassembled screen cursing Apple and reassembled laptop. Booted first time ... excellent! However when shutting down or sleeping the laptop refused to turn back on. A power management unit reset allowed the laptop to switch back on, but the problem remained. Installed power management unit update from Apple, problem remained. Started cycling the knackered battery in an attempt to recover some capacity and 'work' the PMU. Finally, sleep and shutdown started to work properly, turns out the knackered battery prevents switch on by presenting an unexpected voltage to the PMU. Battery update allows deeper cycling of battery, so actually getting a reasonable amount of on time from the old battery and thankfully working sleep and shutdown modes.
So the laptop was returned to good working order, at last.

Dual core home, office and media PC build

15th January 2010
A computer for the home, office and media with a build price of £500 was specified by the customer. Two DVDRW drives were essential, a monitor was not required, gaming not important and the computer must be upgradeable in the future. Due to upgrade path and price point the AM3 socket with DDR3 memory was selected. The computer was built into a smart PC case and had a attractive, low-power reliable wireless keyboard and mouse. The computer spec was an AMD Phenom II X2 545 processor (dual core 3Ghz), 4Gb PC3-10666 DDR3 RAM, 1Tb Samsung F1 high speed hard disk, Radeon HD 2400 Graphics with VGA, DVI and HDMI output for HD televisions, High speed wireless N network card, 52 in 1 card reader and a high reliability Gigabyte motherboard with solid capacitors, two PCI-Ex ports for future expansion with graphics cards and two free memory slots for future expansion. The PC effortlessly played hi-def content due to the Radeon HD 2400 chipset and remarkably played Half Life 2: Episode One at high graphics settings at a very smooth framerate. That's really quite impressive given the integrated graphics chipset and miles ahead of the competition in this area. Also, the processor is actually a quad core chip with two cores disabled! These can be unlocked! Pictures are available here, scroll down to the bottom of the page, it is the second build described.

Marshall Lead 50W valve amplifier

14th January 2010
A respected valve amplifier using two EL34 valves. Problems were a faulty pre-amp valve and capacitor causing distortion well before peak output. The components were replaced, broken knobs repaired, scuffed case repaired and everything given a good clean, returning the unit to good condition and working order.

Pioneer DJM600 mixer

12th January 2010
Missed an entry! The mixer was brought in due to losing 2 channels. This was due to a damaged connecting cable which was repaired. The headphone socket was also loose, so this was tightened and some mis-located LEDs on the front panel put back in the right place.

Pioneer CDJ800 deck

7th January 2010
Deck was skipping and not reading CDs properly. Mains transformer was also buzzing fairly loudly and Cue and Play buttons failed. The laser was OK, a good clean fixed the reading problems and a check to the mains transformer showed that it hadn't failed and was not overheating. The Cue, Play and reverse search switches were replaced and the deck returned to good working order. Update: Despite the deck behaving OK on the bench, the deck was returned as it was intermittently not reading disks. A replacement laser was fitted for parts cost only, curing the problem.

Pioneer CDJ200 deck

6th January 2010
The Cue and Play buttons on the deck had completely failed, with no tactile action left at all. Replacement switches repaired the unit.

Pioneer DJM400 mixer

6th January 2010
The headphone socket had stripped its threads and disappeared inside the mixer. Repair to the socket body and a new nut and washer fixed the mixer.

Quad core high performance PC build 'BEAST'

20th December 2009
A computer for gaming and high performance computing was specified by a customer with a target price of £800. A component list was drawn up and each component researched and chosen considering maximum performance for price with features important for future upgrades. The final spec was 22in widescreen monitor, quad-core Phenom II X4 925 processor, 8Gib of PC10666 DDR3 RAM, 1Tb Samsung F1 HD, Gigabyte ATI Radeon 4870 1Gb graphics card with Zalman cooler, DVDRW and smart, understated Cooler Master Elite 334 case. This is truly a performance beast which chewed through any game I threw at it with silky smoothness at ultra-high graphics settings and zipped though Windows 7 x64 like it was a light snack. Pictures are available here, scroll down to the bottom of the page, it is the first build described.

Samsung VM6000 laptop

17th December 2009
Really old school laptop - 256Mb RAM 400Mhz Celeron 6.4Gb HD and 800x600 screen. Well how much was wrong with this? Dead power adaptor. Faulty keyboard. Dead battery. Hopelessly underpowered. Changed power supply, repaired keyboard, replaced NiMH battery cells and installed linux. So now it is at least usable, still hopelessly slow though.

Toshiba Tecra 8200 laptop

14th December 2009
Unbearably slow XP install and Control Panel and a few other things had been disabled. Computer took ages to boot and ages to open internet explorer. The computer was riddled with viruses and spyware. It was cleaned up, brought up to date and back to working order.

Technics SV-V2 amplifier

8th December 2009
Audio was distorted and channels were intermittent. Due to the age of the amplifier the switches and pots had oxidised. Dismantling the unit to get access at the switches and pots and cleaning and reconditioning the relevant components returned the unit to good working order.

Alesis RA300 and Samson Servo-170

8th December 2009
These two amplifiers were reported to have failed channels. A quick test showed that both amplifiers were working on both channels. The amplifiers were subjected to a rigorous test into an 8 ohm dummy load for an extended period at near maximum rated output power. Neither showed any signs of failure and so were given a clean bill of health and returned to the customer. Perhaps a failed cable or shorted speaker cable was causing the problem.

Old Hammond electronic organ

7th December 2009
This was an interesting piece of equipment! A discrete synthesiser with several processor boards, VCOs, sound generation boards and amplifiers. There were two problems reported, the first being that the Leslie tremolo speaker system was not working and that the arpeggiator wasn't working problem. The loss of sound was due to a failed speaker which was replaced. The arpeggiator problem was not a failure, the synth has a large variety of switches, some that look like indicators only but are actually switches as well, one was engaged when it shouldn't have been.

Logitech Speaker System

1st December 2009
Wire to connect remote control to PC was broken. A replacement cable and 3.5mm jack cured the problem.

Wireless internet problem

30th November 2009
Solved a wireless internet problem due to mis-configuration of router and poor quality wireless cards in the client machines.

Fujitsu-Siemens Amilo laptop

27th November 2009
Laptop would not switch on or charge. The power adaptor was faulty a replacement fixed the problem. The laptop was checked for viruses and spyware, some spyware was removed.

File and e-mail server

19th November 2009
Moved a file and e-mail server for Modus Consulting.

Packard Bell MV-51 laptop

11th November 2009
The laptop would not charge. It was discovered that if the power jack was flexed in a particular direction the laptop would charge and switch on, indicating a failure of either the socket or the soldering of the socket. To get at the socket required the entire laptop to be dismantled, everything! A barely visible hairline crack was discovered in the soldering of the socket - this was repaired and the laptop assembled. The CPU and GPU heat sink compound was found to be too thick and very rubbery - this was replaced with a much more heat conductive alternative and resulted in a much better cooling fan response to heat. The laptop was returned in excellent condition and good working order.

Samsung M40+ laptop

10th November 2009
Wireless internet problems and extreme slowness were the problems with this laptop. A detailed clean up and optimisation of the system resulted in a much improved system response and quick startup. The wireless internet issue was repaired and the laptop returned to the customer in excellent working order.

Sony VAIO PCG-Z1 laptop

9th November 2009
The laptop was slow, several errors occurred on startup, wireless ethernet was not working and neither was the Vodafone mobile internet adapter supplied with it.  A full clean up, removal of corrupted files and troubleshooting driver installation file permissions problems fixed the startup problems and internet access issues and the mobile internet adaptor installed cleanly with the repaired system. The laptop is much more responsive and nice to use, and according to the customer problems were fixed that Sony support could not. The work was done overnight since the customer was leaving for an important business trip and needed the laptop repaired immediately.

Icom 706 transceiver

4th November 2009
More rotary encoder tuning dial problems. Reconditioning of the encoder repaired it, but it may need a replacement in the future. Customer is local so doesn't mind returning it should it need a replacement. Update: Encoder started to fail a week later, so a replacement was fitted for parts cost only.

Numark CDN90 dual CD player

3rd November 2009
Unit came in with deck B unreliable when seeking to a track. Further investigation of the unit uncovered a marginal laser on deck A, a near dead one on deck B and damage to the ribbon cable leading to the laser assembly on deck B. Both decks were replaced - numark spares are relatively cheap - and the ribbon cable repaired. The unit was returned to good working order.

Hitachi 80Gb Laptop HD Data Recovery

23rd October 2009
The drive had been declared dead and unrecoverable by a shop on City Road and the customer decided to see if we could recover the data. Sure enough on first examination it was dead, didn't spin up, not recognised in BIOS. Using precautions against dust, which can ruin a drive, the fault was determined to be that the drive had been dropped and the drive heads has crashed onto the disk surface and jammed the platter assembly inside. The heads were unstuck and moved away from the disk surface into the parking zone, allowing the drive to spin up as normal. Over 90% of the data was recovered from the disk with all important files recovered.

Pioneer CDJ1000 CD deck

15th October 2009
Deck came in with the symptoms: no main display, no button operation, no loading motor operation and the centre display all lit up. Reason for failure was the loss of the +5V supply to the main microcontroller and DSP processors. The power supply was repaired with some replacement components and the deck restored to good working order.

Lenovo J110 PC

8th October 2009
Computer was totally dead, no bios, no beeps nothing. The hard disk was also missing. Visual inspection of the custom motherboard showed 8 dead capacitors, all swollen. Replacement of the capacitors and a new HD brought it back to life. A legitimate install of Windows XP Pro OEM and up to date drivers brought it back to good working order and a custom recovery DVD was made to replace the missing one that was not supplied with the computer. This is a common practice by computer manufacturers which trips up end users when things go wrong and then they ask for £50 for the rescue disks. This repair job is a good example of our capability to recover machines that would otherwise be thrown in the bin.

Mackie 32.8 studio mixing desk

1st October 2009
This is one beast of a mixing desk from Long Row Studios. The desk had several problems, faulty output channel, dead Mix-B output channel and a scratchy pot. The customer also wanted the direct outs modified so that they were pre-fader, pre-eq, post-insert outputs. This was accomplished by working out the circuit of the input jacks, cutting tracks, installing wire-jumps and breaking the circuit in some ribbon cable for each of the 32 channels. The faulty output channel was due to dry joints, and the dead Mix-B channel was due to a dead audio chip. The unit was restored to good working order.

HP Compaq DX2400 Micro-tower

29th September 2009
Computer crashed and restarted during boot up. Culprit was an incompatible or corrupted system service. Computer was cleaned up and restored to good working order.

IT maintenance for Modus Consulting

29th September 2009
We are pleased to announce that Modus Consulting based in Cardiff have chosen us to provide IT build, maintenance, repair and networking services.

Electrolux vacuum cleaner

28th September 2009
Well we don't normally repair things like vacuum cleaners, but anything electrical we can do. The fuse had gone and the power switch had moved inside its housing so it never switched on.

Pioneer DJM-600 mixer

24th September 2009
Headphone jack body had come off, stripped its threads and the nut had worked its way into the master output circuitry and hooked itself around some components. The jack also had blu tack inside it stopping it from working properly. The jack was replaced restoring the mixer to good working order.

Pioneer CDJ-800MK2 CD deck

15th September 2009
Unit had been dropped, breaking the disc retention mechanism. Also, the loading arm bearing was worn causing unreliable load/unload of CD. Every now and then the CD would jam inside the player with a nasty clicking sound. The retention mechanism was repaired and the loading arm wear was repaired returning the unit to working order.

Pioneer CDJ-800 CD deck

8th September 2009
PSU failure caused deck not to take CDs and report error E9101. Some troubleshooting and repair fixed the unit.

Stanton C314 CD deck

27th August 2009
The CD mechanism micro-controller chip died, not the motor driver as I had first thought. This meant a horribly expensive new board which returned the unit to working order. The deck was also converted to 240V UK mains.

Stanton C324 CD deck

26th August 2009
Unit was a 120V model which had been plugged into 240V mains for long enough to cook the mains transformer and some filter components. Replacements brought unit back to working order, luckily the regulator circuitry was hardy enough to withstand double the input voltage and stop the rest of the electronics from being destroyed.

Pioneer CDJ100s

24th August 2009
Internals had jammed due to dust - cleaning out and re-lube restored it to working order.

Denon AVR1906 home cinema amplifier

18th August 2009
Unit went into protect mode immediately after switch on. Faulty connections in the protect circuitry was the problem, fixed and returned unit to working order.

Wharfedale T2811WS 28in TV

3rd August 2009
TV did not turn on, nice burning smell coming from back. A 2kV 2.2nF capacitor had failed, a replacement fixed the set.

Microphones, stands and mixer amplifier available for hire

28th July 2009
We now have a set of three 600 ohm low impedance microphones for hire along with three quality microphone stands. Also available is an 8 channel mixer amplifier suitable for band use in small venues. It has a powerful main output as well as monitor outputs plus 8 channels for microphones, guitars and other instruments.

Hitachi L42VP01U 42in LCD TV

13th July 2009
Set did not turn on. Reason was failure of the internal PSU - failure of the power factor correction circuit and failure of the standby PSU with several fried surface mount components, chips and power components. Replacements and some further troubleshooting brought the TV back to working order.

Kenwood TS-850SAT HF transceiver

5th July 2009
Varying power output on different bands was caused by band-pass filter selection failure. Several corroded tracks were the problem, these were jumped and radio was returned to working order.

Icom IC-210 2m FM transceiver

4th July 2009
Customer wanted CTCSS fitted to this old transceiver to access repeaters - installed cstech unit with jumpers to select the tone frequency, replaced backlighting bulbs and fixed an intermittent audio fault.

Security alarm system

2nd July 2009
Customer brought in main circuit board which he had identified was faulty to see if it could be repaired. A shorted rectifier diode blew the mains fuse. The rectifier was replaced and the board was restored to working order.

Prosound 200 amplifier

1st July 2009
Amplifier would not switch on. Faulty power switch - dismantled, repaired and restored to original working condition.

Doh! Email problems!

30th June 2009
It was brought to my attention that the email above was not working and that emails were being bounced. Sure enough, they were! I am not sure how long this has been occurring for so if you have been trying to get in touch via email, please accept my apologies and try again. I unfortunately was the problem by not configuring my email client properly.

Kenwood TR-7625 2m FM transceiver

27th June 2009
TX power dropped off fairly rapidly in this transceiver. Cause was overheating driver and resultant poor solder joints developed over time. Some replacement components and additional heat-sinking brought it back to working order.

Yaesu FT-290R transceiver

22nd June 2009
This radio was in a fairly sorry state - off frequency by a significant amount, distorted SSB tx, CALL button for 1750Hz tone generation not working, no backlight. Was restored to good working condition by realignment of PLL, replacement of final and duff diode, removal of failed mod to CALL button and replacement of backlight.

Kenwood TS-780 transceiver

18th June 2009
Transceiver was 2.5kHz off frequency. Realignment of carrier generation board and IF board cured the problem.

Nikkai 600W 12V dc to 240V ac inverter

16th June 2009
On switch on, unit tried to start up but tripped with fault indication. A pair of mosfets for generating the AC waveform had died, replacements fixed the unit.

Skytec 8 channel powered mixer/eq/amplifier

15th June 2009
Looks like a handy piece of equipment - 8 channel mixer with effects, eq and high power amplifier all built into a rugged case for lugging around with bands. Same as the Phonic version. Unfortunately, the amplifier had fried in a spectacular fashion - 10 new transistors, a few resistors and a couple of diodes later and it was restored to good working order.

Repair of iPod speaker dock

4th June 2009
Terrible construction led to the failure of the soldering of the surface mount socket that plugged into the iPod. Was repaired, but could not reliably stand up to repeated use so the repair was abandoned and a workaround was implemented of using a charging dock attached over the top of the unit to feed audio into the speaker system. Since it could not be repaired to its original condition, there was no charge however the customer gave £10 for the time spent working on it - thank you Anthony.

Repair of Kenwood PS-430 power supply

3rd June 2009
Was giving out unregulated 23V instead of 13.8V, not healthy for any connected radio! This was a frustrating puzzle, as the pass transistors and regulator were all ok - turned out to be a tiny ceramic capacitor that had failed and turned into a resistor of about 6k. This allowed enough current to flow to fully switch on the transistors allowing a nasty 23V through. Replaced the capacitor, plus a few dried out electrolytic capacitors and a leaky transistor returning the unit to good working order.

Repair of Icom 706 transceiver

28th May 2009
Seized tuning dial due to seized rotary encoder shaft and bearing. Restored to good working order.

Repair of Marantz PM-30SE separates amplifier

28th May 2009
Fault in bias circuit caused overcurrent condition and tripped protect, eventually getting so bad it blew the fuse. Fixed fault and returned amplifier to working condition.

Sound systems and equipment hire available

21st May 2009
We are happy to announce that our sound systems are available for hire. The range is from a small announcement system suitable for public events and children's birthday parties to large systems with up to 8 huge bass bins for heavy duty dance events. See the hire page for details.

Repair of CDJ800

20th May 2009
Laser mechanism gummed up and really dirty. Careful clean and lube returned unit to good working order.

Repair of Music M8 wooden hi-fi

15th May 2009
On/off volume switch and potentiometer completely ruined. Rebuild of potentiometer and replacement of switch returned to good working order.

Repair of TASCAM X-9 mixer

1st May 2009
Faulty left channel on PGM2. Faulty sockets on rear. Scratchy action on cross-fader. Repaired sockets, input stage and reconditioned cross-fader to return to good working order.

Repair of CDJ800 tabletop CD deck

29th April 2009
Faulty laser unit. Replacement restored unit to good working order.

Repair of CDJ100s

23rd April 2009
Faulty rotary encoder and fascia switches. Replacement of each repaired the unit to good working order.

Professional Repair Services website up and running

4th May 2009
We are pleased to announce that the website for PRS Ltd is up and running. Simple design for compatibility with all browsers and we hope it gives a clear impression of what type of business we are running.