[lcaillo]

Many of the power supplies in the last few generations of CRT based Sony sets used a controller IC to drive the FETs made by Shindengen with the type number MCZ3001D or MCZ3001DB. These chips have tended to fail in the high voltage supply (usually IC800x) giving a 6x or 7x blink code. The failure may be intermittent or may be temperature related. The solution is often to change these ICs. This thread will focus on the issues related to this symptom and attempt to provide some guidance for those getting these sets repaired or DIYing the repair.

I consider this to be a reasonable DIY repair, since most sets with 6x or 7x blink codes will be repaired with just the chips. There are some sets, however, that will have more complex problems, and I do not suggest trying to DIY if the chips don't fix the problem. It may be reasonable to change the D board, and a lot less expensive than some repairs to that board. Troubleshooting beyond the ICs is best left to an expert.

 

[lcaillo]

Parts

There are usually at least two power supplies in the sets that use this design that are regulated by the MCZ3001 chips. Some sets have three supplies that use them. The most common failures are in the high voltage drive circuit and result in 6x or 7x blink codes. Other symtoms can include continuous blinking LEDs and completely dead sets. When you suspect one of these ICs, I recommend replacing all of them in the set. They are not that expensive and not that hard to get to in most cases.

Sony sells replacement ICs under the following part numbers (Thanks to the guys at ACME and B&D for the cross references):
6-703-355-01
6-705-810-01
6-704-429-01
6-705-768-01
8-759-670-30

You can also find the part under the Hitachi number CP08451U. They are the same parts, but you will find the Hitachi part to be less expensive, likely half or less than the Sony. Most all of the replacements that I have seen have been the MCZ3001DB version, which is perhaps an improved version, but the difference is uncertain.

Beware of counterfeits, and don't buy the cheapest parts you can find from vendors that do not have a history of providing first quality original manufacturer parts!
http://www.shindengen.co.jp/product_e/nocopy/index.html

We recommend only using certain vendors for ICs. The Hitachi and Sony authorrized parts distributors will be reliable sources of original Shindnegen ICs, and the general parts distributors listed in this thread (like B&D and ACME) would also be good choices:
http://www.hometheatershack.com/forums/diy-repair-maintenance/4396-parts-distributors.html

I have never run across a datasheet for these ICs so if you have seen one, please point me to it.

 

[lcaillo]

Replacing the parts

When you remove the back cover of the direct view sets, the D board, which has the two main regulator circuits that use these ICs will be the board on the left looking from behind. I recommend removing all of the connectors between the boards (they just snap up and hinge over) and all of the wires to the board except those going to the flyback transformer (the big black thing with the red wires coming out of it going to the CRT and CRT board). It is NOT necessary to remove the wires from the flyback and tube. These carry high voltages and the tube can remain charged. The connections are critical and if you damage them or do not replace them properly, you can end up with high oarcs and do a lot more damage. Leave them connected! Once you disconnect everything else and remove the screws, the board will stand up on edge and can be easily serviced with the flyback (aka FBT or IHVT or high voltage transformer) connected to the tube.

Some sites and individuals are recommending that the board not be removed and the plastic support under the chassis simply be cut to allow access to the ICs. This requires that the entire chassis be stood up or that you work upside down. I do not recommend this. First, it is sloppy work to hack up the bottom of the chassis. Second, you can damage connections or the front panel switches, or the CRT board if you are not very careful turning the chassis to the service position. Having the board out and being able to get to it easily on both sides is the better practice. If you don't want to remove the board, you can still get to the ICs from below without cutting the supports, but one of the chips has a couple of pins that are slightly behing the plastic and a little hard to get to. Just remove the board and do it right.

Desoldering the ICs can be done with solder wick or suction. Be careful of the nearby surface mount components. You will have a very bad day if you remove or lose any of these tiny capacitors or resistors that are near the pins that you are working on. Some like to cut the pins and remove them one at a time once the chip is cut free. I prefer to remove the chip intact, as you can damage nearby components or the traces on the board when cutting pins. Note that there is a DOT on one end of the outline of the chip on the board adjacent to pin 1. There is a circle, dimple, or depression on most ICs at pin 1 to identify how the chip goes in. These ICs use this convention. Be sure to put the chip in using the right direction. When soldering the new chip in, note that some of the connections may be on both or either side of the board. You can solder from the bottom for all of them, but make sure that your tip and the lands on the board are clean so that the solder flows through the hole to the other side if needed. Sometimes you have to touch the iron to the other side to get a good flow.

Some recommended tools and materials can be found at these:
http://www.radioshack.com/product/index.jsp?productId=2062731
http://www.chemtronics.com/products/product.asp?id=22
http://www.hakko.com/english/products/hakko_936.html
http://www.mcmelectronics.com/product/DISTRIBUTED-BY-MCM-SABU10191-/SABU10191

and at the vendors in the parts distributor thread:

http://www.hometheatershack.com/foru...tributors.html

Some sites and many individuals recommend using sockets to make future replacement of the chips easier. This does make it easier to change them, but I recommend against it. Sockets vary greatly in quality, and poor connections tend to plague socketed circuits unless very high quality parts are used. As a tech, I have seen many sets with socketed ICs have lots of intermittent problems over the years. In these circuits, there might be a good chance of damaging the FETs (the switching transistors that these ICs control and that carry the current to the transformers) with resistance in some of the connections. Just solder the chips in. If you must use sockets, gets some DeOxit (aka Cramolin) to treat the connections with to be sure that there is good contact.