Hi, I have recently, last two months, began building several of the velleman kits as part of my education in the world of electronics. I started with a radio shack electronics learning lab 28-280 which I followed without any problem through the two books and experiments and then moved on to building the Velleman kits and a few projects from various books. The first kit I built was the MK101 sweetheart blinking LED kit for my fiance. Immediately I thought I was doing things wrong as LED 1-4 (if I remember correctly) would not light up. I found after trying to trouble shoot everything from my soldering joints to ensuring all items were placed correctly on the board (diodes in the correct orientation etc.) that the real problem was a faulty led. Luckily the kit had one extra and as soon as I swapped it out everything was great. I have also built the K8071RS 1W/3W LED driver, K1823RS 1A power supply, K5300 strobe as well as several other small projects from various books on a breadboard, all without issue. The same went with the K4003 amp. I finished building it, used a portable CD players for my source and a radio shack 25.2VAC 2A (12.6 0 12.6) power transformer to supply power, hooked up my speakers and turned on the power and everything worked beautifully. I used the amp for about 10-14 days to listen to music off and on (not continuously) and it sounded great and I saw no signs of heat issues. I used the supplied heatsink, mounting screws and the mica insulator to avoid shorts between the TDA2616 and the heatsink. I used some of my OCZ Freeze thermal conductivity compound on both sides of the mica insulation as suggested in the K4003 assembly manual (the same compound I use between heatsinks and the CPU when I build computers) and even when I played the music fairly loud I felt no signs of excessive heat on the heatsink, in fact it never got any hotter than a faint warm sensation. Then two nights ago I was listening to some music when suddenly there was a loud buzz and when I looked over at the amp there was heavy smoke pouring up from it. I immediately shut down the power to the transformer and disconnected it from the amplifier. I looked over the PCB for any burned areas or obvious damaged parts and everything looked fine on both sides (components as well as all the solder points) except the TDA2616. I desoldered the TDA2616 and removed the heatsink and there in the middle of the TDA2616 was a pea sized burned, blistered area that even created a small crack in the outer shell. The burned area was not on the side facing the heatsink but on the opposite side. Nothing was near the amp when it happened that could have shorted it like an errant wire or anything like that. The amp wasn’t knocked off the desk or anything it just suddenly burned out in the middle of a song. I appologize for the length of this post but since I started with the fact I was brand new to component building, I wanted to show I have had good success and have a good deal of experience with electronics. I have had years of experience with electronics between building computers, repairing computers (both desktops and laptops) and years of experience in automotive electronics. In automotive it ranges from diagnosing and repairing them to installing car alarms systems and audio systems even including the reprogramming of ECU proms from my laptop (not just popping in a store bought pre-programmed chip). But almost all of that is just programming or putting together completed components like sound cards, video cards etc. not building the electronic components from parts like this. I am a 100% disabled veteran and as my physical disabilities have limited so many of the things I have enjoyed doing such as working on cars and building computer systems, building electronics has just kind have become a new hobby that delves deeper into the things I already loved doing and have had experience with. Is there something I could have done wrong or could this just be a faulty IC? I would have thought I screwed up if it burned up the first time I turned it on or even after a few minutes running but I ran it for about two weeks with absolutely no signs of problems, no excessive heat felt on the heatsink no ozone/ burning electronics smell nothing until it just all the sudden went.
Thanks for your patience with this long post and any help would be appreciated.
Sincerely,
Cpl. Jerry W. Gibson II Med. Ret. U.S.Army
If excess heat did not cause the problem, then the only thing we can think of is a too high input voltage.
21VDC is the absolute max. Stress beyond this level can lead to distruction of the IC.
Please contact our US support office for spare parts or repair: (817) 284 77 85.
Would that be a total of 21V DC or AC as the assembly manual states AC current can be directly connected to the unit and in such cases it runs off of a dual AC voltage supply of 2 X 12Vac. I know there is less than 21VAC running to either side but if you mean both sides cannot add up to more than 21V AC or DC, I know it states in the specifications, page 3 of the assembly manual it requires a supply voltage of 2 X 12Vac / 2A (50W transformer recommended) so that would automatically add up to more than 21V. It recommends transformers 212048 or 8012 neither of which I could find through your site, eBay, other online supply shops or my local radio shack. It is also supposed to be overload and short-circuit protection and this is the closest match I could find for a supply voltage transformer. If you still need me to call the number let me know.
21VDC single side, so the total can be 42VDC.
Sorry, at this time we are unable to locate the cause of troubles.
Most likely, we will never know why this happened.
Anyway, the support people in TX are very helpful and they can provide a spare IC.