MZ-700 correct filter capacitors for PSU

User avatar
WinstonSmith
Posts: 4
Joined: Mon Feb 28, 2022 3:28 pm

MZ-700 correct filter capacitors for PSU

Post by WinstonSmith »

Hello, my problem is I'm replacing the two filter capacitors within my MZ700 PSU that recently went pop and thought you guys might be able to point me in the right direction regarding the correct capacitor specifications. i'm in the uk in case that makes any difference.

Thanking you kindly
Winston
timh
Posts: 5
Joined: Sun Jun 13, 2021 4:39 pm

Re: MZ-700 correct filter capacitors for PSU

Post by timh »

Hi Winston,

You don't strictly need to replace them, but they are 0.01uF (C1) and 0.047uF (C2) X2 safety capacitors.

The ones below are those that I've used successfully in mine. The pitch is slightly too small (10mm), but if you're prepared to put up with a slightly bent leg they're fine (The seller also supplies ones with a 15mm pitch which I think might be a better fit). Make sure you get ones rated for at least 250V - these are 275V.

0.01uF - https://www.ebay.co.uk/itm/264758516614 ... 4742485053
0.047uF - https://www.ebay.co.uk/itm/264758516614 ... 4742485056

Tim.
timh
Posts: 5
Joined: Sun Jun 13, 2021 4:39 pm

Re: MZ-700 correct filter capacitors for PSU

Post by timh »

Before and after photographs for reference. It's likely that you'll also need to replace the T500mA slow blow fuse as well.
IMG_20211106_150435_resized_20220305_050949596.jpg
IMG_20211113_133254_resized_20220305_051009626.jpg
User avatar
mz-80a
Posts: 343
Joined: Thu Jan 25, 2018 10:46 am
Location: Devon, UK
Contact:

Re: MZ-700 correct filter capacitors for PSU

Post by mz-80a »

Why do people replace these when they've blown? There's nothing nowadays to filter.
MZ-80A Secrets
https://mz-80a.com/

Sharpworks (Sharp MZ homebrew)
http://mz-sharpworks.co.uk/
timh
Posts: 5
Joined: Sun Jun 13, 2021 4:39 pm

Re: MZ-700 correct filter capacitors for PSU

Post by timh »

Yeah, fair comment.

I replaced mine because I was cleaning and repairing the whole machine at the time, and as it was all in bits it was a case of "why not"! I had a fairly new desoldering / resoldering station I fancied playing with as well ...

I did say that replacement isn't strictly necessary :)

Tim.
User avatar
tingo
Posts: 38
Joined: Wed Oct 31, 2018 9:10 pm

Re: MZ-700 correct filter capacitors for PSU

Post by tingo »

the reason why you should replace them is that they are safety capacitors, they are supposed to blow before the equipment gets damaged or catches fire.
--
Torfinn
User avatar
mz-80a
Posts: 343
Joined: Thu Jan 25, 2018 10:46 am
Location: Devon, UK
Contact:

Re: MZ-700 correct filter capacitors for PSU

Post by mz-80a »

Surely that's the reason for having fuses. The only reason to have the filter caps was to filter out unwanted noise back in the '80s which we don't get anymore nowadays.
MZ-80A Secrets
https://mz-80a.com/

Sharpworks (Sharp MZ homebrew)
http://mz-sharpworks.co.uk/
User avatar
WinstonSmith
Posts: 4
Joined: Mon Feb 28, 2022 3:28 pm

Re: MZ-700 correct filter capacitors for PSU

Post by WinstonSmith »

Thank you timh & tingo for the constructive advice, does it matter which way these capacitors are orintated because both legs are the same lenght?
Regards
Winston
hlide
Posts: 658
Joined: Thu Jan 25, 2018 9:31 pm

Re: MZ-700 correct filter capacitors for PSU

Post by hlide »

tingo wrote: Sun Apr 03, 2022 5:07 pm they are supposed to blow before the equipment gets damaged or catches fire.
Ahem, fuses are for that. Those old caps due to their "paper" conception ALWAYS blow and catch fire after a decade, not because they are used as fuses.
User avatar
WinstonSmith
Posts: 4
Joined: Mon Feb 28, 2022 3:28 pm

Re: MZ-700 correct filter capacitors for PSU

Post by WinstonSmith »

Hi hlide, so your saying they dont serve any other purpose than to remove noise from the RF? If I were to leave them out would I need to bridge the connections.
Regards
Winston
Post Reply