The Rodotron/Wei-ya 666 series chassis info.

[lilshawn]

I've compiled a little bit of info on these chassis as they have become quite popular for their "universal-ness" and quite a few companies are using them for new units.

the main issue with these (especially newer) chassis is LEAD FREE SOLDER. it cracks like an SOB and you get bad connections. It's best if you are having intermittent problems to just take an hour and go over ALL the solder joints with regular leaded solder. Lead free solder is very hard and brittle and the components easily break the solder (oversized through holes and heavy components)

Use caution when soldering the chassis, (especially the neck board if it's failed due to overheated transistors), the tracks will lift right off if your iron is too hot. speaking of which....

secondly, for most tubes, you have to run the gun drives WAY high. this makes the RGB transistors run super hot. They are a TO-126 transistor package with a completely plastic body, thus, is unable to shed much heat. (couple of watts at best) attaching a 90mm or 120mm fan to the bracket blowing on the transistors on the neck board will increase their service life CONSIDERABLY. Consider also another to blow over the deflection chassis. these things tend to run pretty hot.

if you've got an overheated neck board, chances are the small value "104" caps in between the heatsinks are fried. replace them all and relocate them to the back side of the board. this will keep them out of the heat.


B+ variances by sub model:

666A 29 - (15k  - 75.5v) (24k - 114v) (31k - 140v)
666B 29 - (15k  - 55v) (24k - 89v) (31k - 100v)
666C 29 - (15k  - 60v) (24k - 88v) (31k - 103v)
666A 29PDF - (15k  - 73.9v) (24k - 113.1v) (31k - 140.1v)
666A 29PSF - (15k  - 74v) (24k - 112v) (31k - 133v)

[lilshawn]

adding for additional info:

replace color transistors with 2SC3788 (replacing the original 2SC3953) they are a little more common. still, cool the neckboard with a fan.

if your "104" caps are fried go ahead and replace the 100 ohm resistors as well. i've be relocating these parts to the solder side of the board, in between the heatsinks is way too hot and it drives them out of spec.