NM,

One of these might help:

ebay.com link: ws

Rob

NM,
PS seems to break the link (or maybe operator error on this side) - search for item number 281270779341.

Rob

NM,

I struggle to answer your guess with a "yes" or "no" because my design compensates for imperfections in the PDB performance without outright replacing the linear supplies on the PDB. So, the PDB 5 volt supply still needs to drive other boards. A supply weakened by age is better able to do this with the load of the MPU removed (I measured the MPU load at 1/4 watt in my PZ). The PDB also must have a sufficiently working 12 volt supply to drive the switched 5 volt supply generated in the daughterboard. The daughterboard is very tolerant of fluctuations in the 12 volt supply - it will work from 7 volts up to about 30-35 volts.

That PZ of mine will play without the daughterboard if I unplug either the sound card or the GI, but it goes straight into resets with both plugged in. In this "unplugged" mode it is playable but still resets occasionally (maybe 45 mins of playing). Being tired of chasing that gremlin and make the linear power perfect, I lived with it for a long time until I dreamed up the daughterboard.

So, no, it doesn't eliminate the need for best practices like replacing failed capacitors, burnt connectors, failed regulators, and fixing outright shorts anywhere in the machine, but yes, it does allow for a lot more tolerance in the many aspects impacting PDB power supply performance including compensating for imperfections in work performed on the PDB power supplies.

I'm planning a more general announcement of these daughterboards in mid-March when I will have a good supply. In my view your thread (and another I replied to on RGP last week) just begged for my daughterboard so I offered the link to my daughterboard as kind of a "soft launch". If you didn't get the last one on eBay two more are available via a paypal purchase on www.kahr.us. I will have 9 more available on the 26th of Feb. After that, look for the launch in mid-March. I hope this detail doesn't hijack your thread - we should stay focused on discussing your TZ.

Rob

Don't cut the traces - use vinyl screws/nuts to isolate the heat sink from ground so the resistor hack can be un-done more easily. I get the man/machine logic...I'll be around if that calculus changes.

Don't cut the traces - if you are going to do the hack do it in a way that has a hope of being undone. Replace heat sink screws with vinyl screws/nuts from home depot/lowes. If I remember correctly I put a vinyl nut between the board and the heat sink AND on the rear of the board. This isolates the regulator from the copper traces. Tie resistor between ground test point on the top side of the board and the casing and to the heat sink. photo-944.JPG. Incidentally I did this and my PZ still reset... which drove me to design the circuit board I mentioned earlier in the thread.

NM, you got it - particularly like your improved wording of "float the heat sink" as it is more descriptive. Vinyl screws come in limited lengths so plan on cutting down the screw so your board fits back in the back box.

Rob.

Clean work NM. Remember though, a meter can hide what an O-scope can show. This blurry picture is about 2 years old - it shows what a brief collapse in the 5 volt line looks like on a PDB - yes, with the resistor jumper in there to push up line voltage. It's tough to see for a lot of reasons (I took it with my old blackberry, my 30 year-old yard sale-purchased scope (that I revived from the dead) doesn't have screen captures, resets were pretty random so I kinda had to get lucky to catch it), but the steep drop and rapid recovery are clear enough. And it can be enough to take 5.1+ volts down to a reset. Even with the hack you may want to consider using my new daughterboard to move the MPU off the 5 volt line. It is certainly as well thought out as my "Float the heat sink" update to the resistor hack.
photo-979.JPG

Rob