http://65c02.org/images/ak/philips10in.jpg

A couple of recent acquistitions. I've been sticking to small sets lately and couldn't leave these behind. These were quite popular sets here, though these are the first I've owned. Up until now they've always sold for more than I was willing to pay.

On the left is the KA910, on the right the slightly younger KA921 (which actually has an AV input, though it's on a 6 pin DIN connector). Both were built by Sharp for Philips Australia. I don't know if other versions of these existed in other countries. As found the KA921 is dead while the KA910 has a weird fault that I haven't seen before.

http://65c02.org/images/ak/philipska910scn.jpg

Once I deal with that (first stop caps as usual) it should produce a great picture (the camera makes it look worse than it actually is).

http://65c02.org/images/ak/philipska910inside.jpg

The KA910 has a weird 5 pin power connector that I don't have the lead for. I'll probably end up replacing it with a pair of standard connectors. Identifying the AC and DC inputs was easy enough, but I've yet to trace out the purpose of the 5th pin. I suspect it needs to be jumpered to one of the AC pins to enable DC operation.

http://65c02.org/images/ak/philipska921inside.jpg

While the KA921 looks almost identical from the outside it's chassis is much more integrated. I've yet to find anything I recognise as a date code in either set, though I don't think there is more than a couple of years between them.

Both of full of Sharp IXxxx numbered ICs. I know that at least some of the IX series are actually standard parts that that have been renumbered. Does anyone have a cross reference list?

I have a couple of these myself that are awaiting repairs (some rainy day in the future).

I also have a Sharp IC cross reference list. I'll send you a copy sometime during the next few days.

We never had this set in Europe, virtually all Philips portable sets from that age (none under 13") had Philips' own KT2, KT3, KT4 or CTX chassis and were AC only.

Date codes on Japanese ICs are quite cryptical, you'll see something like 9A3, the "9" usually means a 1979 or 1989 manufacturing year, but i don't know how to read the other two digits (which i assume are indicating week or month)

The KA921 is now running (at least on AC, I haven't checked the DC supply yet). The failure was bad caps on the B+ line, and an open resistor and inductor. I also found this split open:

http://65c02.org/images/ak/a250k.jpg

I assume this is a varistor, but I do not know the value. Assuming the 250 is 250V none of the suppliers I know of carry 250V varistors. Am I reading the value wrong? This one reads open circuit, but I do not not remember if these are meant to go open or short when the voltage across them goes high.

It has good color and plenty of brightness, but the convergence is a bit out. It does need some serious degaussing, so hopefully the convergence will improve once I degauss it. I've finally ordered a degaussing wand as I've been doing without one for too long (not specifically for this set, I've found 4 recent sets on the side of the road this week that appear to need nothing more than degaussing).

I still don't have a definite date for either of these. So far my best guess would be that the KA910 is from around 82. Now that I've have a closer look at the chassis it appears the KA921 is actually later than I expected, probably around 86 or even later. The design is similar to Sharp sets that were in a more modern style cabinet. I guess Philips updated the chassis, but recycled the old cabinet design.

The design of both sets is unusual compared to most of the AC/DC sets that I have seen. There are completely separate AC an DC power supplies. Most others that I have seen so far have either a basically conventional AC set chassis that is driven by a step up DC-DC converter when running on DC or 12V is the B+ and it runs from an internal 12V power supply when on AC.

As for other small Philips sets I've seen a mid-late 80s 6" AC/DC set here, but I don't have one of those yet.

My guess is that these sets are from somewhere between 1985 and 1987.

The weird fault on the other set, Is it the shadowing at the top of the picture? I wonder if some of the aquadag on the inside of the crt is peeling off, hanging down and making shadows on the image? you could tell by turning the set upside down and see if that makes the shadow go away, logan

You can use the soldering iron in place of the degausing wand. My buddy the tech did this in front of a customer once, who was very impressed by the smoke generated by the iron (which had some solder on it yet)!

The weird fault looks like a shadow, but is something else. When tuned in those areas are completely dark, but with snow it looks like this:

http://65c02.org/images/ak/ka910snow.jpg

I've heard of the soldering iron trick before, but I think that only works with big AC gun type irons that I've seen, but never used. All of my irons are the low voltage DC temperature controlled type. I've also tried wrapping a couple of deguassing coils from scrapped sets around an old tennis racquet. That made lots of pretty colors, but no lasting results. I've had some success using magnets removed from old hard drives, but that's too much trial and error. If I'd known degaussing wands were only $15 I would have bought one earlier.

The photo's of your KA-910 TV look similar to the fault I have listed below

Fault: Picture being blacked out in corners
Fix: Check / Replace R423 for o/c (10K ohm Resistor)

Les


R423 (10K) is located on left hand vertical PCB closest to the front of TV near (JB) a Blue wire.