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How to check if an AS15 chip is working ok

An AS15 is nothing but a 14 + 1 channel buffer. 15 reference voltages at the inputs are buffered for higher currents on the outputs.

The typical image symptoms of a defect AS15 chip on TCON boards are:

  • solarization - colors, especially darker ones are pink or green, for example
  • faded colors

Many TVs with AUO panels built around 2009 have this defect.

First quick test: does it get hot? It must not. According to the datasheet, its idle current is 10-20 mA. That's not enough to heat up a chip. The last TCON I fixed reduced its total idle current by 150mA with a new chip.

Besides apparent overheating, there is a technique to verify the chip's performance.
Locate testpoints named VGA or VGMA, numbered 1 to 14 or up to 22. Measure those against ground. They must produce a consecutive sequence of decreasing voltage of around 15 down to 0. If there are "holes" or big jumps in between, the chip is defect.

However, the exact values vary between panels. There is no rule.

Also, locate the VGMAREF test point. A typical voltage level there is 15.6V. I had a couple of defect TCONs where VGMA0 measured slightly higher than 15.6V. Apart from that everything looked ok. This is not possible in a working configuration! The reason is the AS15 pulling too much current through the reference resistor ladder and so skewing the reference values.

Note that some TCONs have 0V holes in the testpoint sequence because they only produce 14 or 18 voltages for 22 channels. Those TCONs have pads for up to two 4xOPAs, which are the buffers for voltages #15 to #22. The panels are wired to pick the active outputs accordingly. You must trace the origin of the testpoint voltages whether they lead to the AS15 or to the OPAs.


Onkyo TX-NR 5009 - defect main relay STD-S-109DMR2 - switching itself off - no sound - no image

I have already fixed an 809 and a 515 recently. The 809 had the famous DSP problem and a reflow of the chip fixed it. The 515 had a defect main relay.

I have been using the 809 for a while. It replaced the Marantz SR7007, because its spacial sound representation was much more impressive.

When I saw the former top range 5009 on eBay I just had to have it. The seller said that it did not produce any sound. Thus, I was confident to find a familiar fault. I was wrong.

When I plugged it in cold straight from the box it started with a strange rattling noise from one of the relay. That couldn't be right. A check of the software versions showed that the DSP was ok. Good.

A few moments later - KLACK - the mains fuse triggered. This was reproducible. I unplugged the huge analog transformer and the fuse stayed on. A relay was acting up though. So, this relay switched the transformer on and off in a too quick succession. This triggered the fuse due to the inrush current.

First I suspected a defect relay. However, with time and warm-up the problem disappeared. I went ahead, connected the TV and got no image. Not even the Onkyo logo. Sound from analog and optical inputs was basically ok, albeit a little too silent. The HDMI input and output seemed to be completely dead. My PC did not recognize it as a sound device via HDMI.

So it had to be the HDMI board, which controls and digitally processes everything in this device. That's intimidating to begin with. So let's focus on the basics first. What improves with increasing temperatures? Capacitors! Although the measurements of the various DC supplies looked fine, I pulled off one of the SMD electrolytics and its ESR was abysmal!

All of those suckers had to go. Seven super low ESR Nichicon HD took their place. I have plenty of them in stock specifically for Onkyo HDMI board rework.

On the top side I mounted two heatsinks on the DSP (right corner) and on one image processor to keep those two under better working conditions. Five caps had to be replaced there.

After putting the board back in the image was still missing. What the heck? A factory reset and the monster was good to go!

The 5009 is a huge piece of hardware and on a much higher level than the cheaper ones. The sound compared to the 809 is a lot smoother and more natural. Onkyo has put more effort into the digital domain, obviously, because the analog amplifiers are identical, with a little more juice in the power section.

Update - Relay Trouble

The receiver worked fine for a while and one evening it went pop! and the sound was gone. Everything else was normal. I noticed that it cooled down and my immediate suspicion was that the main transformer had switched off.

The main relay died. Its coil was open. What is it with those Onkyos that their relays die like flies?

Finding a replacement turned out to be difficult. The original part in the 5009 is a STD-S10DMR2. Notice the 2 at the end! Smaller Onkyos use the SDT-S-109LMR2.

Both types are designed with a reduced power consumption in mind. Let's look at the data sheet:

In forums I read that the voltage is too high. I soldered in a resistor with the specified value of the coil and measured more than 10V until the speaker relays clicked. Then it went down to a little more than 9V.

It was impossible to find the original DMR2 part, only the DMR. Also, the 9V types were unobtainable except from Aliexpress. On eBay I ordered 12V STD-DMR. In the meantime I found a spare 10A 12V relay for testing. After adjusting R9109 it worked fine, the receiver is back alive. The voltage is now between 11.5 and 10.5 volts.

So, the relays are not plug and play when you replace the low power with the normal types! You must adjust R9109 to bring the voltage to the proper range. Also, take notice if it is a LMR (5A) or DMR (10A) type! The size is the same, so, if you are planning to put some on stock, the DMR will fit all receivers.

The DMRs have a higher inrush current rating of TV-8. In that sense, they are quite unique. During my search for a replacement I only found TV-5 ratings.

I think that the low-power DMR2 / LMR2 relays were garbage and Onkyo hit them with a little too much voltage. It does not surprise me that I could not find any of those types. Only the normal ones.

Surprisingly, only the main relay got too much voltage. The ones for the secondary transformers were all inside the spec.


More IR6500 tweaks - silencing fan - fixing flipped polarity of thermocouple socket - adjusting temperature offset - run bottom heater independently

Silence the fan

The fan is annoyingly loud. It is a line voltage fan, so you cannot just put some PC fan in there. The remedy is simple. I used four rubber mounts I had left over from my last PC build. I dumped the grill. It is unnessesary.

What a relief!

Non-standard K-Type socket polarity

This device is full of surprises. I damaged the original thermocouple recently and plugged in another K-Type I had lying around. Surprise! The temperature figures were going down instead of up when I heated it.

Why was that? For what reason ever, they managed to flip the polarity of the K-Type socket. It is non-standard! The original sensor also had the polarity wrong. Dafug?

It is easy to fix though. Just open the bottom cover, unscrew the wires and put them back on in reverse.

To make positioning of the sensor possible without fiddling with tape, I bough an adjustable holder HERE. The integrated magent is too weak. I glued a powerful neodym on top of it. This thing sticks!

Very nice, sensitive, yet a little fragile sensors are THESE. They need a readjusment of the controller, which I will address next.

My sensor setup looks like this:

Adjusting temperature offset

The new sensors were off by a few degrees and I investigated posibilities to fix this. Thankfully there is a decent manual available for the controller. The manual that came with the IR6500 is utter useless.

It works like this:
  • Measure the temperature in boiling water to get the difference to a reference  My new sensor was 6°C off in reference to 100°C.
  • Press PAR/SET and hold until the controller switches to configuration mode. You will see some text instead of the usual temperature reading.
  • Press PAR/SET until OFSt appears.
  • Use the arrow keys to offset the difference.
  • Press PAR/SET until the normal display returns.

Run bottom heater independently

It always annoyed me that it wasn't possible to use the preheater alone, without running a program. I like to have the bottom heater at its max temperature and the board pre-heated before I even start the reflow process.

It is easy. All you need is three wires and a toggle switch.

The bottom controller's terminals 4 and 5 output the control voltage for the heater power relay. Terminal 5 goes straight to the relay. Terminal 4 is looped through the main controller's terminal 7, which gets connected to terminal 6 when a program starts. Terminal 6 goes to the heater relay.

  • Remove the wire between main controller terminal 6 and the bottom heater switch.
  • Wire the toggle switch to choose between terminal 4 of the bottom controller and terminal 6 on the main controller. The common wire goes to the heater relay.
In ON position the bottom heater controller works independend from the main controller. With the temp set to 300 I get around 110°C on the upside of the boards.


Pimping the IR6500 with an Elstein RFS80 top heater

I have tried to solder the CPU of Philips QFU TV boards twice and failed, because the temperature distribution of the top heater was so bad that the chip sank in at one edge and got lifted up at the diagonally opposite edge. All the tedious reballing work in vain! My suspicion is that the top heater of the IR6500 is rubbish.

On eBay I found a seller who offers a Made in Germany Elstein RFS80 heater:

It also comes with a reflector, which will help to concentrate the heat even better.

So I set off to mount this thing into my station.

You can tell already from the way the heating wires are positioned that Elstein had put more thought into this. Everything is arranged around the center whereas in the original heater the energy is wasted in places where you never need it. Moreover, the surface is not even.

The new heater fits perfectly well into the original holder bracket. The one angled side with the screw holes needs to be bent to stand upright (right side on the image).

Next, I drilled four holes at the sides of the head and reused the original screws with no problem.

The silly fan, which is now even more useless than it already was, had to go. With the reflector and the mounting bracket there will not be much heat going into the head. Besides, the air has no place to escape at the bottom, anyway.

Done. Besides a slightly off center, everything turned out pretty good. With the new heater, centering needs to be more precise than with the old one because of its shape.

Unfortunately I broke the temperature sensor recently. As this one has the reverse polarity than the usual ones (they will yield negative temps), I had to order a bunch from China. So, no testing right now. I'll post a followup when the next reballing session takes place.


Building an EDS LeakSeeker 89!

The EDS LeakSeeker is a unique device to find shorts. Watch the videos on YouTube by EDS or check the description on the EDS website. Unfortunately EDS stopped selling them a few years ago. But there is a way to build one yourself!

During a routine search after used LeakSeekers (which don't exist, everybody is keeping them!), I came across THIS PAGE.

I wrote a mail to Dave Miga of EDS, who designed this cool device, and after he had confirmed that shipping to Germany is possible, I ordered a board from the above source, and a parts kit from Dave.

This wasn't exactly cheap, but this thing is so unique and useful, I just had to build it! I will enjoy it until the end of my days as I don't think that anybody will design something similar anytime soon.

And here it is, the assembled LeakSeeker on my bench in a prototype stage. I have yet to find a nice case for it. The original case has no space for 9V battery blocks. I like portable testing tools. The thingy draws less than 100mA when it is testing and 30mA idle.

It is not difficult to build, yet there are two things I (almost) messed up:
  • Make sure that the resistors left to the gain switch are all the way in, otherwise they might short with the metal case of the switch.
  • Handle the 0.05 ohms wire carefully and don't bend its legs. The legs are welded to the wire and can break off.
During my first tests I thought it didn't work because it can take quite a while until it moves from the green LEDs to the yellow and produces a deeper chirping sound.

Here I am playing around with a testboard that has a 10 Ohms resistor to simulate a defect component. The sensitivity of the LeakSeeker is astounding. I can hear the tonal difference of 1cm distance on a trace in the low gain setting.

Wild plans: Arduino touch frontend!

I think I will use the LeakSeeker to start with Arduino development. I never found any real use case for me with these things, but now, with the amazing Nextion touch displays controlled via the Arduino Nano, I will try to give the Seeker a fancy new touch screen interface. I think I'll choose the 3.5 inch enhanced Nextion model. It's reasonable big and fat finger friendly. This is going to be fun (and much work).

The reengineering of the LED control is the hardest part. They are organized as a 3x3 matrix with TTL levels. The switches are easy. They can be replaced with small 5V relays.
It will also be possible to add a volume control with a FET, because the chirping can be quite intense.

Basically, I think with this combination it is possible to build a touch interface for many devices. Get rid of all switches, LEDs, potentiometers. The EDS CapAnalyzer is another candidate.

This is the answer I got from Dave to my inquiry. I think he won't mind me showing it here.

The LeakSeeker and CapAnalyzer parts listed below are available. 
Purchase includes all data required to build your own CapAnalyzer and LeakSeeker; the list is shown below.
 LeakSeeker 89 is unique in the world and nothing can do what it does. Check out the eds-inc website for more info.

All prices in US Dollars:
EDS-89 or EDS-88A kit of all pcb parts (including programmed mcu) to mount to pcb (pcb not included) $89
Programmed MCUs ONLY:  IC set for CapAnalyzer88A $25, mcu for LeakSeeker89 $18.
3-piece gold-plated test lead set for LeakSeeker $18
Special tweezer probe assy for CapAnalyzer $29.
No other parts in stock, however the sources below show where to buy or fabricate the pc board, overlays and cabinet.
FEDEX or DHL shipping to Germany 81371   $49.45
Payments are in US Dollars via Paypal to
Or we can send you a pro-forma invoice that you can pay with a credit card or PayPal. Just email us with your list, your name, address, and phone number. FEDEX and DHL will not ship without a phone number.

This data list will be emailed to you with your purchase:
Eds88ar1 BOM  Complete bill of materials for EDS-88A CapAnalyzer series II PCB and Drill files for EDS-88A.
eds88As2fp.pdf  Front panel for CapAnalyzer 88a series II
EDS-89 BOM bill of materials for EDS-89 Leakseeker
EDS-89 overlay graphics for Leakseeker, includes drill and mill dimensions for OKW case
EDS-89 pcb.pdf Parts layout for EDS-89. Don't really need it as pcb will have silkscreen anyway...
EDS-89 TOP LAYOUT.jpg Just another graphic of main panel in EDS-89 pcb gerber and drill files for EDS-89
All EDS products use pc boards fabricated by 
These pcb makers will have a small minimum of boards that must be made so there will be extras;
There are also many people selling these extra spare pc boards on eBay; do a Google search or see email list below.
Or anyone advertising in magazines like Elektor or Nuts and Volts. Or get spare boards from other kit builders. Try these, most have purchased parts kits and may have spares...

Cabinet for EDS-88A is the 36TDB from Simco
Cabinet for EDS-89 is the OKW Teko TENCLOS PULPIT 590.9 order from or or

User manuals (and alignment instructions for EDS-88A) on the eds website


The Andonstar ADSM302 microscope - more versatile than you think!

BGA reballing and main board repair means staring at very small components. I am 51 years old now and need some decent magnification to be able to see these little balls, chips, resistors and whatnot.

The high end microscopes by Amtech or Eakins, which you see in various repair videos, are prohibitively expensive for occasional use, and also very bulky for my restricted workbench.

The new Andonstar ADSM302 came at the right time for me. After checking some reviews on YouTube and reading all about it, I bought one on eBay from Germany for 200 EUR.

This thing is great! The picture quality is more than I ever need. I'll show you some modifications, which I haven't seen so far anywhere. Those make it even more useful!

Turn the base by 180°

The base is not terribly small, but still annoying. I want my stuff to lay flat on my bench. It is dead easy to mount the holder to point away from the base. An old disk drive attached as a counterweight and there you have it, a flat workspace underneath the microscope!

Mount in two positions

That's not all. The optics can be attached to the holder in two positions, thanks to a second groove below the focus ring. The manual doesn't reveal that.

Large "zoom" range!

And now look what a fantasic range you get from this little microscope. We are looking at a CPU taken from a Philips TV. Beautiful full HD images on a 22 inch monitor.

Top position:

Bottom position, still enough room to work under it:

I dare to say that this is the best microscope in the 200€ range today. Second to none.


IR6500 Rework Station Modification - Ineffective bottom heater due to overly thick glass

First of all: get the original manual for the controller HERE. The description in the IR6500 manual is an unreadable desaster.

It did not take me long to realize that the thick glass of this rework station is absorbing most of the energy from the bottom heater. The 800W of the heating element were basically ineffective.

Also, the station has trouble with the peak temperature of 230°C in the reflow program. I need to adjust the top heater very close to the chip if I like to reach it. Closer than I feel comfortable with. The manual says >2 centimeters. That's actually the maximum distance. Further away and the peak temp will never be reached. If a window is open or a fume extractor running, it is even worse. I think that a good heating support from the bottom will stabilize the temperature.

I got inspired by this YouTube video.

Screw the warranty, I want this thing to work! Let's remove the top:

Oh dear, I have used the station only a dozen times and the temperature sensor shield was already burned and coming off. The sensor had no contact with the heater anymore. This thing gets too hot for any glue. A stupid design.

This is garbage. I am not interested in the temperature of the heater, anyway. I want to know the lower temperature of the board, if anything.

The sensor has a rugged, metal sleeve. So let's pull it outside through one of the slits:

The downside of the top cover:

Unscrew the frame that holds the glass and remove the glass. This thing is really thick!

I got a metal grill from a hardware store. I cut it to the right size and screwed it to the cover:

The difference in heat radiation is remarkable. The glass takes everything away!

Sweet, now let's do a preheater test without running a program and measure a few things:

With the bottom temperature set to 100C, the board heated up nicely to the specified temp in a few minutes. Note that with the glass on, the board would go up to about 40C max after ages with the heater set to 250! 
The heating element has around 300C, which should be well inside its spec.

Well, it is no surprise that a relatively cheap chinese rework station is not quite finished and has a sloppy build quality. On the other hand, those things are simple and easily tweaked.