Building a replacement MTX PSU

About original Memotech hardware.
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1024MAK
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Re: Building a replacement MTX PSU

Post by 1024MAK » 26 May 2015 15:53

wyerd wrote:Looking good Mark! Will you be posting circuit diagrams and a parts list as I'd like to make a 110v version?
Of course ;-)

The only differences between a 230V (220V to 240V) and a 110V to 120V version are the mains transformer, the mains on/off switch (which has a neon in it) and the current rating of the mains input fuse (I suggest a 2A instead of a 1A for 110V to 120V mains).

Mark

wyerd
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Location: Upstate New York. USA.

Re: Building a replacement MTX PSU

Post by wyerd » 26 May 2015 15:56

1024MAK wrote:
wyerd wrote:Looking good Mark! Will you be posting circuit diagrams and a parts list as I'd like to make a 110v version?
Of course ;-)

The only differences between a 230V (220V to 240V) and a 110V to 120V version are the mains transformer, the mains on/off switch (which has a neon in it) and the current rating of the mains input fuse (I suggest a 2A instead of a 1A for 110V to 120V mains).

Mark
Great. Thank you.

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1024MAK
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Re: Building a replacement MTX PSU

Post by 1024MAK » 26 May 2015 16:18

Inside continued:
Inside #05.jpg
Inside #05.jpg (230.2 KiB) Viewed 2130 times
Inside #06.jpg
Inside #06.jpg (153.67 KiB) Viewed 2130 times
Inside #07.jpg
Inside #07.jpg (262.37 KiB) Viewed 2130 times

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1024MAK
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Joined: 24 Dec 2012 03:01
Location: Looking forward to summer, in Somerset, UK

Re: Building a replacement MTX PSU

Post by 1024MAK » 26 May 2015 16:21

Inside #08.jpg
Inside #08.jpg (257.09 KiB) Viewed 2130 times
Inside #09.jpg
Inside #09.jpg (219.2 KiB) Viewed 2130 times
Inside #10.jpg
Inside #10.jpg (456.89 KiB) Viewed 2130 times
A parts list and schematic will follow (hopefully) later in the week.

Mark

wyerd
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Joined: 13 May 2013 23:16
Location: Upstate New York. USA.

Re: Building a replacement MTX PSU

Post by wyerd » 26 May 2015 18:07

Can we see it powering a MTX? Not that I'm doubting it of course! :D

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1024MAK
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Re: Building a replacement MTX PSU

Post by 1024MAK » 26 May 2015 18:30

If you grab a time machine and visit Memofest 2014 you can/could of seen it powering a real MTX computer :D

I forget now if there any pictures taken at Memofest 2014 showing it.

Mark

wyerd
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Joined: 13 May 2013 23:16
Location: Upstate New York. USA.

Re: Building a replacement MTX PSU

Post by wyerd » 26 May 2015 18:42

1024MAK wrote:If you grab a time machine and visit Memofest 2014 you can/could of seen it powering a real MTX computer :D
Mark
:lol: :lol: :lol:
I wish I could've been there and the upcoming ones, but it's a bit costly coming from the USA. Maybe I should start a North American Memofest? I think I'm the only one over here though!

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1024MAK
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Re: Building a replacement MTX PSU

Post by 1024MAK » 28 May 2015 00:52

Schematic:-
New MTX PSU Schematic V1-02.png
New MTX PSU Schematic V1-02.png (49.62 KiB) Viewed 2034 times
Mark

Edited to update slightly amended schematic
Last edited by 1024MAK on 16 Jul 2015 17:41, edited 2 times in total.

wyerd
Posts: 88
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Location: Upstate New York. USA.

Re: Building a replacement MTX PSU

Post by wyerd » 28 May 2015 20:04

Looks simple enough......... :shock: :shock: :shock:

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1024MAK
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Re: Building a replacement MTX PSU

Post by 1024MAK » 31 May 2015 20:35

Okay, in the attachment is a parts list / BOM. It's nearly all UK based, but I'm sure overseas readers will be able to pick up suitable alternative parts ;-)
The file is an Excel spreadsheet that has been zipped up :mrgreen:

And here is a text listing (long entries have been cut-off). Read the Excel spreadsheet for full details ;-)

Code: Select all

Circuit Ref                Part Details                Manufacturer    SupplierSuppliers   QTY Price Pack PK QY  PKs                       Notes
Resistors:                                                                                                                                
R1         100Ω 5% 250mW metal film or 0.5W or 1W metalVishay: MBB02070Rapid   62-7446       1 £0.03 £2.68 100     1 100r Mrs25 1% Metal Film Resistor - Pack of 100
R2         1.2kΩ 5%  250mW metal film or 250mW carbon f                Rapid   62-2102       1 £0.02 £1.71 100     1 1k2 0.6w Metal Film Resistor - Pack of 100
                                                                                                                                          
Capacitors:                                                                                                                               
C1         2200uF 16V electrolytic, 5mm pitch/spacing                  Rapid   11-0300       1 £0.34 £0.34   1     1 85°C 2200U 16V Radial Lead Aluminium Electrolyti
C2         100nF ceramic multilayer, 5mm pitch/spacing                 Rapid   11-3454       1 £0.03 £0.03   1     1 0.1uF +/-20% 50V Y5V P:5.08mm  Radial Ceramic Ca
                                                                                                                                          
Diodes:                                                                                                                                   
D1, D2     1N4001 or 1N4002 or a higher voltage rating 1N4001          Rapid   47-3130       2 £0.09 £0.04   1     2 1N4001               
                                                                                                                                          
LEDs:                                                                                                                                     
LED1       5mm standard green LED                      Kingbright L-53GRapid   55-0868       1 £0.06 £0.06   1     1 Kingbright L-53GD 5mm Green LED Diffused 30mcd
           Suitable panel mounting plastic clip        Kingbright: RTF5Rapid   55-0260       1 £0.21 £0.21   1     1 Kingbright LED Bezel Clip (Prominent) 5mm
                                                                                                                                           
Modules:                                                                                                                                   
           LM2577 step-up DC-DC converter.                             eBay/che'261211800    1 £1.63 £1.63   1     1 LM2577 DC to DC Adjustable Converter Step-up Cir
           I used a Chenyao19870517 LM2577 DC to DC adj                                                                             
           Set the output voltage to 16V before fitting                                                                             
                                                                                                                                   
Fuses:                                                                                                                             
F1         1A A/S or T (suitable for fused IEC chassis Siba: 70-007-65/Rapid   26-0386       1 £0.16 £0.16   1     1 1A 20x5mm Antisurge Ceramic Fuse
F2         5A A/S or T 20mm x 5mm                      Eska: 522.524 5ARapid   54-3160       1 £0.08 £0.76  10     1 ESKA 522.524 5A Slow Blow Glass Fuse 5x20mm
           Panel mounting fuse holder suitable for the CamdenBoss: CFH0Rapid   26-0191       1 £0.48 £0.48   1     1 Low Profile Fuseholder
           Insulation Boot for above                   Bulgin: 11327   Rapid   26-0187       1 £0.46 £0.46   1     1 Insulation Boot Medium
F3         1A A/S anti-surge/T time delay 20mm x 5mm   Eska: 522.517 1ARapid   54-3146       1 £0.08 £0.76  10     1 ESKA 522.517 1A Slow Blow Glass Fuse 5x20mm
           PCB fuse clips, 5mm pin pitch, suitable for ESKA: 120.800H  Rapid   49-0536       2 £0.12 £0.06   1     2 ESKA 120.800H Fuse Clip For 5x20mm Fuses 6.3A
                                                                                                                                                                 
Transformer                                                                                                                                                      
T1         50VA 230V primary, twin 7.5V secondary windiVigortronix: VTXRapid   88-3928       1£12.38£12.38   1     1 Vigortronix Chassis Transformer 230V 50VA 7.5V+7
                                                                                                                                                                     
Switch:                                                                                                                                                              
SW1        Miniature red neon mains dual pole rocker swSCI: R13-73C-02 Rapid   75-0300       1 £0.96 £0.96   1     1 DPST Illuminated Rocker Switch
                                                                                                                                                   
Socket:                                                                                                                                            
SKT1       Fused IEC Chassis Plug                      Inalways: 0717-CRapid   23-2100       1 £0.91 £0.91   1     1 Fused IEC Chassis Plug, takes 20mm X 5mm fuse
                                                                                                                                                               
Plug:                                                                                                                                                          
PLG1       6 pin DIN plug suitable for the MTX         TruConnect      Rapid   20-0280       1 £0.34 £0.34   1     1 6 Way Insulated DIN Plug
                                                                                                                                             
           Miscellaneous items:                                                                                                              
           ABS plastic box (or a suitable metal box).  Bradford ConsultMaplin  KC89W         1 £7.74 £7.74   1     1 Plastic Box MB7 Black 177x120x83mm
           Strip board                                                                       1               1                                       
           Various sizes of heat shrink (to insulate an                                                                                              
           Small cable ties                                                                                100     1                                 
           M4 countersunk machine screws, washers, and                                       2                                                       
           M4 Solder tag (for the earth connection to tPJP: C4         Rapid   33-1815       2 £0.09 £4.39 100     1 Solder Tags Plated M4 Pack Of 100
           M3 machine screws, washers, and nuts to fix                                       4                                                      
           Circular Spacers M3, 4mm long               PJP: EL4Ø3      Rapid   33-3611       4 £0.21 £5.34 100     4 Circular Spacers M3 4mm Pack Of 100
           Countersunk M3 nylon machine screws to hold Anixter: 0040411Rapid   33-5042       2 £0.06 £3.15 100     2 Countersunk Head Slotted Metric Machine Screws M
           Countersunk M3 nylon nuts to hold the IEC maAnixter: 0080729Rapid   33-5072       2 £0.06 £3.10 100     2 M3 Nylon Nuts Pack 100
           Mains rated, stranded equipment wire 16/0.2m                Rapid                                         Equipment Wire 16/0.2mm
           Stranded equipment wire 7/0.2mm, rated at 1.                Rapid   01-0108         £1.53 £1.53           Equipment Wire 7/0.2mm
           Stranded equipment wire 24/0.2mm, rated at 4                Rapid   01-1100                               24/0.2mm Equipment Wire
           6 core cable rated at 1.4A or better, lengthKabeltronik: 095Rapid   49-0478       2 £2.26 £1.13   1     2 Kabeltronik 095062409 UL-LiYY 6 x AWG 24 Unshiel
Mark

Edit: updated to correct an error in the parts list/BOM.
Attachments
My replacement MTX power supply unit - parts list V1-02.xls.zip
(9.96 KiB) Downloaded 94 times
Last edited by 1024MAK on 16 Jul 2015 18:21, edited 4 times in total.

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