DECserver 700 PSU fix, H7881-AA

[Adrian Graham]

Hi folks,

Thanks for the links, I should’ve said I work for a DEC/HPE reseller so I can get replacements through work but I thought there might be some folk here who’ve fixed one before and might have some tips.

Cheers again

Adrian


> 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
> 
> 
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-- 
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