Modifying the Pioneer DV-525 DVD Player

Daniel G. Wright
July 17, 2000

Output Board

Moving on to the output board, this is the board with the RCAs attached and should house the DAC chip as well. I leave the main processor board alone. Caps and Resistors Replace the electrolytic cap in the digital out circuit with a Black Gate 1000uf - 16V cap. Then solder a 0.1uf X7R ceramic cap directly across the leads of the electrolytic and remove the surface mount ceramic bypass cap from the board for which the X7R replaces. There is also a 75ohm surface mount resistor in the digital signal path. I removed this and replaced it with a 75ohm Caddock. Here I was able to use an existing solder pad for one of the resistor leads and drilled a small hole at one end of the solder pads for the surface mount resistor, leaving just enough of the pad to solder to. Keep the leads of the Caddock resistor as short as possible. You may also want to replace the two capacitors on the output board that make up the video PS and another electrolytic right at the S-video out with Panasonic FAs 1200uf or greater (match or exceed the voltage ratings of the stock caps). There is not a great benefit to greatly exceeding the voltage rating of the stock caps. More capacitance for the same voltage rating is better. Finally, placing a small amount of blue-tak or rope caulk on the top of each of the electrolytic caps will reduce any vibration. Digital Out Replace the stock digital out (el-cheapo on mine) with a Canare 75ohm digital coax RCA jack ($6.95 from Michael Percy Audio). I soldered short 19ga Kimber wire leads from the RCA jack to the PCB. If you want even better performance, replace the RCA jack with a Canare 75ohm BNC connector. Oscillator Locate the crystal oscillator on the main processor board. It will be a metal can. On mine, it is oblong, about 2/3'' long and 1/4'' wide. Damp this with a piece of blue-tak or rope caulk by applying a small cap of damping material to the top, taking care not to touch any of the conductive leads. This will reduce jitter by protecting the crystal from outside vibrations...it makes a big difference. Jon Risch has a somewhat more elaborate take on this tweak.

Miscellaneous

Chassis I damped the lid of the unit with (if you can believe this) Armstrong 12''x12'' adhesive backed vinyl floor tiles from your local Home Depot/Lowes for the bargain price of $0.59 per square foot. I cut a piece to fit the top of the lid and the sides. You may want to use some additional glue or construction adhesive to affix the floor tile to the lid. There have been reports of the original adhesive softening with heat. If you have a noisy transport mechanism, I would also recommend gluing a couple of cork squares under the lid as well, directly over the transport. You can also apply blue-tak or rope caulk to the transport mechanism and to places throughout the chassis wherever there appears to be 'rininging' or a flexible surface. RFI Control I applied 1/4'' wide strips of copper tape to form a copper shield cap over the top and sides of four of the ICs on the main processor board. Be very careful not to wrap the copper tape over the sides and contact any of the leads. For the larger chips, I overlapped multiple pieces of the 1/4'' wide tape to cover the entire top of the IC and overlapped the sides a little also. There are five main chips on the board, but one of them has a conductor portion on the top surface, so that one was avoided. I then very carefully assured continuity between all of the copper strips forming a continuous conductive shield by putting a drop of solder at the points where the pieces of tape overlapped. You don't need to solder the entire seam between each piece of tape. You just need a path, so one drop per seam is adequate. Work quickly with the soldering iron when doing this and do it in steps if need be. Don't overheat the IC! Take individual strands of CAT5 (24ga wire) and tack solder one end of the wire to the shield. Twist the wires together and tie them into a screw directly grounding them to the chassis. This serves to shield the ICs and drain any radiated RFI to ground to protect the rest of the system from being affected.

Summary
	That's all that I can think of for now. I will add more information to this list as I learn of it. These tweaks are for using the unit as a dedicated transport only. I am sure that these will also benefit the analog outs to some extent, but that is not the focus of these mods. I will be doing some mods to the analog outs soon as well and will post them when I figure it all out.

Daniel G. Wright dwright@internetcds.com