I'd thought you'd use someting clever
Don't worry about the pic. I've been looking at strain reliefs and I needed one anyway as I'm going to be converting my Beeb's PSU to 120v and I'll be replacing the power cord with a moulded US one. I've ordered a couple as they're only 10 cents each but I'll need to order the tool from eBay.
Building a replacement MTX PSU
Re: Building a replacement MTX PSU
I managed to find the same case you used.
Re: Building a replacement MTX PSU
You can see the inside of the cable on the left hand side at the bottom of the case, under the stripboard (with the large electrolytic capacitor and fuse) in the pictures of this post
Coming up over the weekend, I have some pictures of how I cut the hole for the mains switch and of the IEC mains connector.
Mark
Coming up over the weekend, I have some pictures of how I cut the hole for the mains switch and of the IEC mains connector.
Mark
Standby alert
“There are four lights!”
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer in Somerset later in the year
Not as many MTXs as Dave!
“There are four lights!”
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer in Somerset later in the year
Not as many MTXs as Dave!
Re: Building a replacement MTX PSU
Hi David. I've looked through your list. The fuse holder you have selected is for the wrong size fuse. I suggest this one:wyerd wrote:Can you check over my shopping cart when you have a minute as I want to make sure that I've ordered the correct items and with it connecting to mains voltage I don't want it to go bang! I wish there was a Rapid over here as I've had to get bits the parts from different places, but the bulk is from Mouser.
http://www.mouser.com/ProjectManager/Pr ... 9517318b8e
Mouser Part No: 576-03455LS1HX020
Manufacturer Part No: 03455LS1HX020
http://uk.mouser.com/ProductDetail/Litt ... lY4U2gc%3d
The 100nF capacitor (594-K104Z15Y5VF5TL2) is fine from an electrical standpoint, but has a lead pitch of 2.5mm. But you should be able to bend the leads to fit.
Everything else is fine
Mark
Standby alert
“There are four lights!”
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer in Somerset later in the year
Not as many MTXs as Dave!
“There are four lights!”
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer in Somerset later in the year
Not as many MTXs as Dave!
Re: Building a replacement MTX PSU
Many thanks Mark for checking it over and for letting me know the errors.
I look forward to seeing the latest pics you promised!
I look forward to seeing the latest pics you promised!
Re: Building a replacement MTX PSU
So, next: preparing the plastic case.
Tools I used: fixed metal rule, tool with a sharp point (for marking), battery drill, metal HSS drill bits or wood drill bits (they have to be sharp), needle files, various shape and sizes, somewhere to work where you don't get told off for making a hell of a mess As with all these, measure twice! Mark once. Very carefully line up the drill (set to a slow speed), double check that you are drilling INSIDE the marked line, and carefully drill each hole: Once you have an outline, angle the drill slightly so that you "join the dots" Then carefully file the excess plastic away until you have a neat hole that is just large enough for the connector: Of course the last picture here is a test fit!
Tools I used: fixed metal rule, tool with a sharp point (for marking), battery drill, metal HSS drill bits or wood drill bits (they have to be sharp), needle files, various shape and sizes, somewhere to work where you don't get told off for making a hell of a mess As with all these, measure twice! Mark once. Very carefully line up the drill (set to a slow speed), double check that you are drilling INSIDE the marked line, and carefully drill each hole: Once you have an outline, angle the drill slightly so that you "join the dots" Then carefully file the excess plastic away until you have a neat hole that is just large enough for the connector: Of course the last picture here is a test fit!
Standby alert
“There are four lights!”
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer in Somerset later in the year
Not as many MTXs as Dave!
“There are four lights!”
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer in Somerset later in the year
Not as many MTXs as Dave!
Re: Building a replacement MTX PSU
The mains switch is done the same way, but you have to be a bit more careful, as this is a snap in type and too big a hole would be a disaster!
Mark
More tomorrow Mark
Standby alert
“There are four lights!”
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer in Somerset later in the year
Not as many MTXs as Dave!
“There are four lights!”
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer in Somerset later in the year
Not as many MTXs as Dave!
Re: Building a replacement MTX PSU
Standby alert
“There are four lights!”
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer in Somerset later in the year
Not as many MTXs as Dave!
“There are four lights!”
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer in Somerset later in the year
Not as many MTXs as Dave!
Re: Building a replacement MTX PSU
Before fitting items to the case, it is far easier to connect some of the wiring first.
Strip about 5 to 6mm of the insulation, gently twist the wire strands together using your fingers, then using round nose pliers form a "U" loop. This will give the soldered connection added mechanical strength.
Pass the stripped wire through the hole on the terminal of the item and if needed, flatten the "U" loop with smooth flat nosed pliers. Cut off any excess wire strands,then solder.
Once the joint is cool, inspect it. If happy, cut a suitable length of a suitable size heatshrink tubing. Slide over the wire and terminal and using a hot air gun (I use a gas soldering iron with the hot air "tip") shrink it down. When shrinking it, keep slowly moving the heat source, as if you try to just do one section at a time, the heatshrink will wrinkle and/or burn.
I also use heatshrink tubing to keep the wires together in tidy bundles. Mark
Strip about 5 to 6mm of the insulation, gently twist the wire strands together using your fingers, then using round nose pliers form a "U" loop. This will give the soldered connection added mechanical strength.
Pass the stripped wire through the hole on the terminal of the item and if needed, flatten the "U" loop with smooth flat nosed pliers. Cut off any excess wire strands,then solder.
Once the joint is cool, inspect it. If happy, cut a suitable length of a suitable size heatshrink tubing. Slide over the wire and terminal and using a hot air gun (I use a gas soldering iron with the hot air "tip") shrink it down. When shrinking it, keep slowly moving the heat source, as if you try to just do one section at a time, the heatshrink will wrinkle and/or burn.
I also use heatshrink tubing to keep the wires together in tidy bundles. Mark
Standby alert
“There are four lights!”
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer in Somerset later in the year
Not as many MTXs as Dave!
“There are four lights!”
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer in Somerset later in the year
Not as many MTXs as Dave!
Re: Building a replacement MTX PSU
Don't forget all the other holes. Here I show how to do the holes for the transformer fixing machine screws. Once you have drilled the holes, use a countersink drill bit (or similar). Go careful as it is very easy to cut too much, or too little and use a slow speed. Every so often try putting the machine screw in the hole to check if it fits nicely. The idea being that the head of the screw is flush, or almost flush with the case.
With most fuseholders, the hole they need is NOT round. Instead it is round-ish with a flat side. If you just drill a round hole that it will fit in, it will turn in the hole . So drill an undersize hole, then get to love filing , while trying the fuse holder every so often until it fits through... Don't forget to pass the wires through the fuseholder insulation boot and the plastic nut before connecting both ends of the wires You can see the various stages of making the LED and the associated resistor connections. Using small round nose pliers, form the leads into a small coil. Note the resistor leads are far easier to make into a coil. This makes the connection more robust and easier to solder. Cut off any lead that sticks out the end of the coil, then over with heatshrink sleeving.
Mark
With most fuseholders, the hole they need is NOT round. Instead it is round-ish with a flat side. If you just drill a round hole that it will fit in, it will turn in the hole . So drill an undersize hole, then get to love filing , while trying the fuse holder every so often until it fits through... Don't forget to pass the wires through the fuseholder insulation boot and the plastic nut before connecting both ends of the wires You can see the various stages of making the LED and the associated resistor connections. Using small round nose pliers, form the leads into a small coil. Note the resistor leads are far easier to make into a coil. This makes the connection more robust and easier to solder. Cut off any lead that sticks out the end of the coil, then over with heatshrink sleeving.
Mark
Standby alert
“There are four lights!”
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer in Somerset later in the year
Not as many MTXs as Dave!
“There are four lights!”
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer in Somerset later in the year
Not as many MTXs as Dave!