Matt - I'd say you may as well replace the TIP-35, 36 pass transistors, especially if you're getting in there to apply fresh heatsink compound - I replaced a shorted pass transistor on a "tired" PS3 recently. Keep the old ones as used spares!
Frank On Tue, Feb 2, 2010 at 12:29 PM, Ike Zimbel <[email protected]> wrote: > Yes, what Jim said. Other notes: > -I don't have any real experience with the PS-4, but someone sent me some > pics once, and that one, at least, showed some signs of running too darn > hot! > -Please don't use the dab of silicone! The supplies will be stationary, so > vibration won't be an issue. Silicone dabbing just makes life difficult for > future repair people...like me! > -The low supply voltages are kind of intriguing. I would change the main > filter caps first and then measure again. I have seen supplies have trouble > reaching their designed voltage if these caps were bad. > -36 volt supply is only half wave rectified and un-regulated, so it may > look a bit rough, should look better with new caps. > -Keep a sharp eye out for any signs of overheating in the +/-18v output > sections, especially around the fuse holders, TIP-35, 36 transistors and the > large power resistors. If you see signs of this, a good de-soldering, clean > up and re-soldering is in order. Replace parts that have a crystalline look > to their leads...they have had too much heat. > -The OVP trimmer should not affect output voltage. > Will try and write more later. See previous posts about internal mechanical > ground connections between the various metal parts of the supply. > best, > Ike > > > On 2/2/2010 12:06 PM, Jim wrote: > >> >> >> Hi Matt, >> >> Sounds like you have a great plan for the supply. I usually go to the next >> higher voltage and capacitance for the ElCaps; IIRC they may have been a >> better physical fit. If you can find the higher temp versions than the >> standard 80C that would be a good choice. Otherwise seems you've got it >> right. Good luck! >> >> Regards, Jim >> >> >> At 06:41 AM 2/2/2010, you wrote: >> >>> Hello everyone, >>> >>> First off, I should say that I'm a relative neophyte when it comes to >>> all things Neotek (and console tech-ing in general), so hopefully I >>> don't ask too many silly questions... >>> >>> Short story is that I'm starting work on slowly sprucing up a 24 ch. >>> (20 ch. currently installed) Elan that belongs to a friend of mine >>> (Casey Rice...he posted here before Christmas about the meters on some >>> channels spontaneously switching between peak and VU modes.). IIRC, >>> the console was built in '91. >>> >>> First up on the list of things to do is to give the power supply a >>> good going over. Until last weekend, the console was running off a >>> PS3-01 that is now getting a bit tired (I say was, as it is now >>> running off a PS4-01 that was purchased a while back as a spare - by >>> the way, do the PS4s generally run a bit hotter than the PS3s? This >>> one certainly seems to, though I didn't really check exactly how hot >>> the PS3 was before so that's a subjective observation...) >>> >>> The PS3 appears to be in original condition with little or no work >>> done on it. As mentioned, it is still operational, but no longer quite >>> up to scratch. Adjusting the +/- 18V trimpots to their maximum >>> settings gives me +16.6V and -16.33V, with the console connected. >>> However I have not tried adjusting the over voltage protection trimpot >>> as I didn't have the 15k resistor handy to set it as described in the >>> documentation. >>> >>> The phantom supply looks good (reading 48.6V) but the logic supply is >>> also down a bit; -22.5V instead of -25V. >>> >>> The unregulated meter supply is reading 34V but has a 100Hz, >>> approximately 2Vp-p sawtooth ripple on it. >>> I guess this is causing the occasional random meter problems described >>> in the other thread. AFAIK it hasn't happened again since I switched >>> over to the PS4. >>> >>> Noise/ripple looks good on all the other supplies though when checked >>> on the scope though and the console noise floor seems to be fine. >>> >>> There's not a whole lot of evidence of serious overheating or much >>> burnt out except for the 0.1uF ceramic capacitor across the input to >>> the logic supply, which has split open and also the 1N5401 diodes >>> across the TIP35/36B transistors look a bit toasty (especially on the >>> +ve supply). >>> >>> The plan is to replace all of the electrolytic capacitors, the burnt- out >>> ceramic, those 2 diodes, renew the heatsink compound on all the >>> silicon and then re-calibrate (and also check short-circuit >>> protection) per the documentation. >>> >>> Basically just wanted to ask if anyone has any advice or >>> recommendations on other things check or replace? Or does this seem >>> like an appropriate first (and hopefully last) step? >>> >>> Also, I was planning to stick with Nichicon caps; thinking using the >>> PW series (low impedance, long-life, 105degC): >>> >>> >>> http://au.mouser.com/ProductDetail/Nichicon/UPW1V472MHD/?qs=V4Q4DNvfnliPoJjHSDt1Yg%3d%3d >>> >>> Obviously they are physically much smaller than the original caps and >>> have a smaller lead pitch (will probably put a drop of silicon under >>> each one to help support them). Is this a good cap choice, or should I >>> consider upsizing them? My inclination would be to do so as a matter >>> of course, but it looks like the PW series tops out at 4700uF in 35V >>> and anything larger that I could find wasn't "Long Life". Happy to >>> accept suggestions for other caps - this was the best I could come up >>> with after a while of bouncing between the mouser and nichicon websites. >>> >>> Thanks in advance and best regards, >>> -Matt. >>> >>> ------ >>> >>> View the list online at: >>> http://www.mail-archive.com/[email protected] >>> >>> You can unsubscribe at anytime by sending an email to mailto: >>> [email protected] with "unsubscribe neotek" in the message body. >>> If you have any difficulties, or questions --please send an email to mailto: >>> [email protected]. >>> >>> The Neotek list is lovingly hosted by Catapult Web. Remember that any >>> message or reply sent to the list will be automatically forwarded to all >>> subscribers. >>> >>> Vive Le Neotek! >>> >>> Thanks. >>> >> >> >> ------ >> >> View the list online at: >> http://www.mail-archive.com/[email protected] >> >> You can unsubscribe at anytime by sending an email to mailto: >> [email protected] with "unsubscribe neotek" in the message body. If >> you have any difficulties, or questions --please send an email to mailto: >> [email protected]. >> >> The Neotek list is lovingly hosted by Catapult Web. Remember that any >> message or reply sent to the list will be automatically forwarded to all >> subscribers. >> >> Vive Le Neotek! >> >> Thanks. >> >> >> > -- > Ike Zimbel > Zimbel Audio Productions Ltd. > Toronto > 416-720-0887 > > "Studio House Calls". Authorized Warranty service for Allen& Heath, > Clear-Com, Drawmer, Soundcraft, SPL and Yamaha. Repairs and upgrades to > analog audio equipment including: AMEK, dbx, Neve, Neotek, MCI, Soundcraft > and more. Ask about our RF Frequency co-ordination services! > www.zimbelaudio.com > > > ------ > > View the list online at: http://www.mail-archive.com/[email protected] > > You can unsubscribe at anytime by sending an email to mailto: > [email protected] with "unsubscribe neotek" in the message body. If > you have any difficulties, or questions --please send an email to mailto: > [email protected]. > > The Neotek list is lovingly hosted by Catapult Web. Remember that any > message or reply sent to the list will be automatically forwarded to all > subscribers. > > Vive Le Neotek! > > Thanks. >
