DECserver 700 PSU fix, H7881-AA

On 27 Feb 2019, at 18:06, Electronics Plus via cctalk <cctalk at classiccmp.org> wrote: https://shop.mitservices.com/product/digital-dec-server-700-psu-h7881-aa/ in stock in the UK. -----Original Message----- From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Gregory Beat via cctalk Sent: Monday, February 25, 2019 12:48 PM To: binarydinosaurs at gmail.com; cctalk at classiccmp.org Subject: Re: DECserver 700 PSU fix, H7881-AA Adrian - ASTEC is now owned by Emerson Power (UK address below). Emerson Power Catalog (find the 57 watt models): https://www.mouser.com/catalog/supplier/library/pdf/Emersonpower_catalog.pdf PowerClinic in Dallas/Fort Worth area services a large number of Switch-Mode power supplies. http://portal.powerclinicinc.com/web/services Power Clinic Inc. 3732 Arapaho Rd Addison, TX 75001 USA == H7881-AA (Refurbished), $177.00 USD https://www.tamayatech.com/parts.php?g=H7881AA H7881-AA Power Supply, 57 watt , $450.00 USD https://www.ipsystemsinc.com/shopping/pgm-more_information.php?id=630 ASTEC - Europe (UK) Waterfront Business Park Merry Hill, Dudley West Midlands, DY5 1LX United Kingdom Telephone: +44 (0) 1384 842 211 Facsimile: +44 (0) 1384 843 355 == From: Adrian Graham To: "General Discussion: On-Topic and Off-Topic Posts" Subject: DECserver 700 PSU fix, H7881-AA Hi folks, My trusty DECserver has bitten the dust in a silent and non-violent way with the fuse still intact so has anyone got tips on troubleshooting? I know it's the PSU because I 'borrowed' another PSU from work and the unit is running again. It's an ASTEC unit under the hood, and in my experience of fixing the older types like the AC8151 (Memotech, TRS80 II/III, Osborne etc) the chief culprits on an utterly dead PSU are the input caps and/or the small 220uF or 330uF startup cap in the feedback circuit. I haven't checked bitsavers etc for a schematic yet, does such a thing exist? Hopefully the ASTEC board has a model number on it. Cheers -- adrian/witchy Owner of Binary Dinosaurs, the UK's biggest private home computer collection? t: @binarydinosaurs f: facebook.com/binarydinosaurs w: www.binarydinosaurs.co.uk --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus