The Sinclair QL Forum

Hi forum ,

Is there anyone who can help me with details on the internal-poweregulator-upgrade as sold in the early days to replace the 7805.

Heat kills , and the upgrade was a switching regulator without the big heating issues.

i would like to build one , to replace the 7805 in my ql.

any info is welcome



techy

Now, I've not yet tried any of these yet, but on some other machines (e.g. Spectrums and ZX81's) some people have fitted switch mode converters like Traco DC-DC Converters TSR-1 Series 1 A or RECOM R-78Bxx-1.0 DC/DC-Converters.

Mark

1024MAK wrote:Now, I've not yet tried any of these yet, but on some other machines (e.g. Spectrums and ZX81's) some people have fitted switch mode converters like Traco DC-DC Converters TSR-1 Series 1 A or RECOM R-78Bxx-1.0 DC/DC-Converters.

Mark

We (German ZX-Team) use those switching regulators like the recom in our ZX80 replicas and ZX81s.
There are also (at least two) other producers. Recom is the "oldest".
The picture from ZX81s are quite sensitive to noise (ripple from the switching) on the VCC, someone found out that a small coil between the 5V Output of the recom and the mainboard minimizes this.
for more info look here. The size of the coil needed corresonds to the current drawn
In case of lingual problems google translator may be helpful. If that is not sufficient, do not hesitate to ask.

Thanks for all answers ,

buying a dc/dc converter is much cheaper than making one myself.

i have found several .

Even ebay has sellers which offer those.




Thanks

update !! , i have ordered this one ( see picture ) and hope it will do .



techy