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Checking MDAC caps

hc25036

pfm Member
I've had an secondhand MDAC for a few months and am very happy with it. Needless to say, the spectre of bulging caps raised in a few posts has me wondering whether to check mine out while I still have the chance to sign up for MDAC2 at a great price.

I'm usually very confident at opening up any kind of kit for a look-see and build my own PCs without a second though, but MDAC seems to have about 40 identical screws that could all need removing to get a view at the board! Can't find anything online, so can someone shed some light for me? Is there a guide somewhere?
 
Only the 8 Torx screws on the sides of the case need be removed.

Seat the Torx bit firmly in the screw with a light tap, there have been instances where the screws have been 'stuck' so need a tap first.

Once the screws are out the the front panel (held to the mainboard with a ribbon connector) can be twisted, or the ribbon pulled off.

The back panel and mainboard slide out from the rear of the case.
 
So there was a kind of 'secret handshake' involved! Many thanks misterdog.

Now I just need to decide how badly I want to know...
 
So, now I know..

Caps on the power daughter board are a bit bulgy (is that a word?):

IMG_0158_zpsez0s6anf.jpg


The others look OK to my untrained eye:

IMG_0152_zpsw3kiycbv.jpg


IMG_0156_zpswi35tis3.jpg


IMG_0153_zpslxm3wbpl.jpg


IMG_0155_zpsspf67eye.jpg



Am I in need of therapy? Is it worth getting the main power caps done on their own? I know LesW has done this for others, but he seems to have more than enough on his plate just now!
 
Oh dear, those don't look too healthy! :( Yes they at least need to be done.

Wonder if the seller knew...the cost of replacing all the caps in this won't be cheap, though not blatant rip-off NAIM levels - there's lots of caps to replace - a straightforward job for someone with solid soldering ability, but I wouldn't try to DIY it otherwise.

Such a shame these units got hit with this cap issue :/
 
The Caps on the main board look fine though, they are the PITA.

If you want a good increase in SQ. do away with the power board and feed the mainboard with 5 rails of clean DC.
 
The Caps on the main board look fine though, they are the PITA.

If you want a good increase in SQ. do away with the power board and feed the mainboard with 5 rails of clean DC.

I wish I knew what that meant and how to do it!

I guess I need to find out about the costs for mdac2 and hope mine holds out until a board swap is ready....
 
The 5 PSU caps you have BULDGING are quite simple to change, I think !! the main PCB is four layer which makes it a Pain in the Arse.
Ive not worked on the PSU board but I think it would be simpler, it is at least more accessible.
Where are you based ?

You only need to really worry when you have the yellow electrolyte seeping out !
As seen on mine, marked with red felt tip..

R_IX1jPk8rlccN3QyUwHDPl5rryLAU1Qf3sZprJJQcM2PwHL9fxFSmpdbLN9xR-Dt2bEZU21ryoR31A43AFf8z_C1x2M28g5iE6-JPA8_k0KOhcKkIqrLcNi3aQgEssT8hZ2RKqoawOWIIkA-ouT6CSPdmjusj_v-sXPJWWwZK6znBakgPu7DaOUs68367_LObRwThTBejGh64W40lyouY7yZ0ypvdZzgt_METSYHFV9v4TWWo1NZgCwYiQxYxrvx8tsdq6n7ln4Dm68Q0jyZ8XQfY4AUjCYjyrExXoNibEj2Jdu3Og6dQe1fWDKUPpipvhXYIeIDbvh3lTfzw9SWUkp-m5cJS3WGalBqC0DscXA74QMMwDklNqXhEMbUBzp3hfGR4WEHBOHm09MfHQdwWwWQDPDZ4crHmK78sCfnwqfjMKe7Zmjd7FNvMDLe28I8MBQY7nk0JU4ytg71Ho-n1T8Jx9OvhW8Uys42jZT6vkqJ_ALsiLxr0aU6QLZRf6Wwg7pvsj1LSu5SMTQfukEanmJcXB_nYAoFg0HeOHsD_kI-ZWn6FZGP-rsKw-T2jQJ1FRbHZSysxx6WDM9IhVAPw_z54mcRUE3LgeEHOqMLlzJz3VfqiYJ=w479-h638-no
 
Thanks guys - I'm always amazed at how helpful pfmers are. Killie - DIY would be an option for me, but at £500 for failure and being on the 240v end rather knackers any confidence! In the Audio room I've been told that AIG will service for £48 plus parts, but I'd need to find a replacement DAC for a few weeks.

Misterdog - I'm near Reigate in Surrey...

Rick
 
It's not 240V into the MDAC, the power brick supplies approx 14V AC to the MDAC. So long as you put the caps in the correct way there isn't really anything that can go wrong.
 
It's not 240V into the MDAC, the power brick supplies approx 14V AC to the MDAC. So long as you put the caps in the correct way there isn't really anything that can go wrong.

**Slaps self on head** - of course! It's a confidence issue as I've not done much pcb soldering although what I have done was OK. Desoldering will have to be learned though.
 
If you were nearer Sheffield we could sort it for you.
There may be someone nearer to you though.

DIY tip cut through the cap leads, leave long lead on PCB remove cap from board.

This enables you to desolder one lead at a time from the board.
 
Many thanks misterdog. I think it is within my skill set but outside my competence (©)! I'll start a new thread with an appeal for local help, and if that fails go to IAG for a service even though life here will be quiet for a month or more while they do it.
 
Coward - just get an old PC board to practice on first.

We will walk you through it.

Imagine the deep sense of satisfaction you could have..
 
I know, I know. But, worst case it's around £80 and 4 weeks to get IAG to do it vs me bricking it while getting desoldering (new to me) wrong. Essentially, I'm a wuss...
 
It's not as difficult as it seems.

I use a fusible alloy with a low melting point. Wood's alloy (70°C) or Rose's alloy (90°C). Such as, for example: http://www.ebay.co.uk/itm/Roses-meta...8AAOSwbsBXmKrK .

Caution! Wood's alloy toxic, contains cadmium. Looking good ventilation. Rose's Alloy is more secure.

A drop of this solder dissolves solder on the board and reduces the melting point of 150 ° C or lower.

Capacitors easy desoldering any soldering iron. The holes are easy to clean. It's easy and fast. Without damage multilayer PCB.

This solder must be removed before installing new Cap’s.

Best Regards
 
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If you get stuck, I'll do it for you for nowt, just get the PSU caps

I'm down south a lot so could pick it up.
 


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