ZX81 cooling fan

Discussions about Sinclair ZX80 and ZX81 Hardware
Moggy
Posts: 1507
Joined: Wed Jun 18, 2008 1:00 pm

Re: ZX81 cooling fan

Post by Moggy » Mon Nov 13, 2017 3:26 pm

Quick update.

Fitted fan to case lower half with slats removed tried at 9 and 5v. Nice little airflow but noisy at 9v.
Fitted case top half and discovered that even though there is sufficient clearance the airflow reduced dramatically. :(

My next step is to do a smoke test to see where and if any air is being dragged in, with m/board fitted.


I would add that I'm not trying to steal Lardo's thunder here as this is firmly his baby, just want help and add some of my experience :D .

User avatar
siggi
Posts: 760
Joined: Thu May 08, 2008 8:30 am
Location: Dauernheim, Germany
Contact:

Re: ZX81 cooling fan

Post by siggi » Mon Nov 13, 2017 3:28 pm

Andy Rea wrote:
Mon Nov 13, 2017 3:04 pm
No no no your all wrong... you gotta go big :D

https://youtu.be/EM2G5vLGcQQ

:mrgreen: :mrgreen:
If those fans are used, all socketed ICs within the Zeddy would need a safety belt to remain in their socket :mrgreen:

Siggi
My ZX81 web-server: online since 2007
http://zx81-siggi.endoftheinternet.org/index.html

Lardo Boffin
Posts: 627
Joined: Sat Nov 26, 2016 1:42 am

Re: ZX81 cooling fan

Post by Lardo Boffin » Mon Nov 13, 2017 3:29 pm

Blimey. :o
ZX81 iss 1 (bugged ROM, kludge fix, normal, kit)
Iss 3 with ZXVid, another in nearly perfect box
TS 1000 iss 3, ZXPand AY, ZX8-CCB & ZX-KDLX
TS 1500
TS 2000
Spectrum 16k (iss 1 s/n 1499)
Spectrum 48k
Toastrack + DIVMMC future

Lardo Boffin
Posts: 627
Joined: Sat Nov 26, 2016 1:42 am

Re: ZX81 cooling fan

Post by Lardo Boffin » Mon Nov 13, 2017 3:32 pm

Moggy wrote:
Mon Nov 13, 2017 3:26 pm
Quick update.

Fitted fan to case lower half with slats removed tried at 9 and 5v. Nice little airflow but noisy at 9v.
Fitted case top half and discovered that even though there is sufficient clearance the airflow reduced dramatically. :(

My next step is to do a smoke test to see where and if any air is being dragged in, with m/board fitted.


I would add that I'm not trying to steal Lardo's thunder here as this is firmly his baby, just want help and add some of my experience :D .
I’m happy for any assistance. :D

Again with the low tech but if I wet my fingers and put them near the edge conntector I can feel the air being pulled in. But not too near... :|

I had considered lighting and blowing out a few matches to see where the smoke went...
ZX81 iss 1 (bugged ROM, kludge fix, normal, kit)
Iss 3 with ZXVid, another in nearly perfect box
TS 1000 iss 3, ZXPand AY, ZX8-CCB & ZX-KDLX
TS 1500
TS 2000
Spectrum 16k (iss 1 s/n 1499)
Spectrum 48k
Toastrack + DIVMMC future

User avatar
1024MAK
Posts: 1778
Joined: Mon Sep 26, 2011 9:56 am
Location: Looking forward to summer in Somerset, UK...

Re: ZX81 cooling fan

Post by 1024MAK » Mon Nov 13, 2017 4:17 pm

siggi wrote:
Mon Nov 13, 2017 3:28 pm
Andy Rea wrote:
Mon Nov 13, 2017 3:04 pm
No no no your all wrong... you gotta go big :D

https://youtu.be/EM2G5vLGcQQ

:mrgreen: :mrgreen:
If those fans are used, all socketed ICs within the Zeddy would need a safety belt to remain in their socket :mrgreen:

Siggi
A three-point racing harness by the looks of it... :shock:
:lol: :lol: :lol:

Mark

User avatar
1024MAK
Posts: 1778
Joined: Mon Sep 26, 2011 9:56 am
Location: Looking forward to summer in Somerset, UK...

Re: ZX81 cooling fan

Post by 1024MAK » Mon Nov 13, 2017 4:19 pm

Lardo Boffin wrote:
Mon Nov 13, 2017 3:32 pm
Moggy wrote:
Mon Nov 13, 2017 3:26 pm
Quick update.

Fitted fan to case lower half with slats removed tried at 9 and 5v. Nice little airflow but noisy at 9v.
Fitted case top half and discovered that even though there is sufficient clearance the airflow reduced dramatically. :(

My next step is to do a smoke test to see where and if any air is being dragged in, with m/board fitted.


I would add that I'm not trying to steal Lardo's thunder here as this is firmly his baby, just want help and add some of my experience :D .
I’m happy for any assistance. :D

Again with the low tech but if I wet my fingers and put them near the edge conntector I can feel the air being pulled in. But not too near... :|

I had considered lighting and blowing out a few matches to see where the smoke went...
Not gone looking for them for some years, but there use to be smoke sticks available... light them and instead of just burning with a flame, they would just smolder and smoke...

Mark

Moggy
Posts: 1507
Joined: Wed Jun 18, 2008 1:00 pm

Re: ZX81 cooling fan

Post by Moggy » Mon Nov 13, 2017 4:33 pm

Good and bad news.

First the bad news.

Just gluing the fan to the case doesn't work and draws no smoke in through any orifice.this I put down to a lack of headroom above the fan and back pressure even with the slats removed.


The good news.

(Collectors look away now) I hacked the lower case so that the fan actually fits inside the aperture unrestricted and any gaps filled in.
Did the smoke test with fan running firstly at 4.5 v (regulated) then 6v (regulated) as the power supply I used has no 5v strangely enough and deepest of joy I found smoke was drawn in through both the expansion slot and the side openings to a degree I would consider adequate for the job.

Tonight I intend to attach this lower case temporarily to a good,working,cased zeddy and leave running for several hours and test to see if the hot spot above the ULA that normally appears on the top case manifests itself and take it from there.

Conclusion?

Yes it works quietly when using a 12v fan at reduced voltage and air does flow through the case and may actually do some good which tonight may tell,but you have to ask yourself is it worth the effort of butchering the case?
To me the answer is yes because I use not collect zeddies so I'm up for anything re modding, a pristine mono Zonx unit now is now a stereo Zonx box forming part of a dual stereo 6 channel turbo AY setup is just one example of my attitude to this but collectors may opine differently.

If you do decide to have a go at this mod bare in mind that in my experience cheap sintered bearing or bushed fans tend not run so easily when lower voltages are used but the ball bearing types run quite readily at lower than expected voltages.

Lardo Boffin
Posts: 627
Joined: Sat Nov 26, 2016 1:42 am

Re: ZX81 cooling fan

Post by Lardo Boffin » Mon Nov 13, 2017 5:02 pm

Excellent news Moggy. :D

I personally have no issue in butchering the case of my everyday zeddy so it doesn’t run hot. Ultimately the damage is underneath and cases are far less scarce than ULAs.
ZX81 iss 1 (bugged ROM, kludge fix, normal, kit)
Iss 3 with ZXVid, another in nearly perfect box
TS 1000 iss 3, ZXPand AY, ZX8-CCB & ZX-KDLX
TS 1500
TS 2000
Spectrum 16k (iss 1 s/n 1499)
Spectrum 48k
Toastrack + DIVMMC future

User avatar
1024MAK
Posts: 1778
Joined: Mon Sep 26, 2011 9:56 am
Location: Looking forward to summer in Somerset, UK...

Re: ZX81 cooling fan

Post by 1024MAK » Mon Nov 13, 2017 5:15 pm

I try to only buy ball bearing type fans, as the extra money is worth it in reduced noise and longer life. However, do check that the item you get is actually a ball bearing type, because sometimes the description of a product does not match the item supplied... :twisted:

Mark

User avatar
gammaray
Posts: 259
Joined: Sun Apr 17, 2016 1:44 am
Location: Texas

Re: ZX81 cooling fan

Post by gammaray » Mon Nov 13, 2017 6:41 pm

What is the thickness of the micro fan 10mm? I found a smaller ones...
1 or 2 in parallel?

https://www.ebay.com/itm/SEPA-MF15B-05L ... Sw~fpZuY3Z
Finish what you start. Truth is over the mountaintop or six feet under.
4 x TS1000, 2 x TS1500 , 2 x timex 2040 printer, 1/2 x timex 2020 cassette deck, ZXPAND, ZeddyNET, ZXBlast..., unfinished Spectrum...Still no life!

Post Reply

Who is online

Users browsing this forum: No registered users and 1 guest