'homemade eprom eraser'
I've bought a UV tube, a starter, and a choke in order to build a homemade
eprom eraser but am unsure as to how they should be wired together.
I'm told that the choke should be in series with the tube but there are
three connections on the choke.
Can anyone help?
Pasi T Mustalahti
|On Wed, 4 Mar 1998, Robin Cocker wrote:
> Hi everyone,
> I've bought a UV tube, a starter, and a choke in order to build a homemade
> eprom eraser but am unsure as to how they should be wired together.
> I'm told that the choke should be in series with the tube but there are
> three connections on the choke.
> Can anyone help?
PTM: If you kill youself with 220V, don't come to tell me !
Be carefull, UV makes uou blind and gives you skin cancer !
PTM, utu.fi, pasi.mustalahtiutu.fi, ptmustahttp://www.utu.fi/~ptmusta
Lab.ins. (mikrotuki) ATK-keskus/Mat.Luon.Tdk OH1HEK
Lab.engineer (PC support) Computer Center OI7234
Mail: Turun Yliopisto / Fysla, Vesilinnantie 5, 20014
Pt 02-3336669, FAX 02-3335632 (Pk 02-2387010, NMT 049-555577)
In message <002b01bd4794$dfd74180$cdrcc.lboro.ac.uk>, Robin 16f0e783
Cocker <STUDENT.LBORO.AC.UK> writes R.C.Cocker-94
>I've bought a UV tube, a starter, and a choke in order to build a homemade
>eprom eraser but am unsure as to how they should be wired together.
>I'm told that the choke should be in series with the tube but there are
>three connections on the choke.
>Can anyone help?
I solve a lot of problems by just putting the UV tube in a standard
fluorescent fitting. I've checked mine, and the ballast only has two
connections. Perhaps yours has a ground connection. Try checking the
resistance of each lead to the case.
Leon Heller: lfheller.demon.co.uk leonhttp://www.lfheller.demon.co.uk
Amateur Radio Callsign G1HSM Tel: +44 (0) 118 947 1424
See http://www.lfheller.demon.co.uk/dds.htm for details of my AD9850
DDS system. See " "/diy_dsp.htm for a simple DIY DSP ADSP-2104 system.
UV Eprom eraser works great exactly as many of you suggested. Total cost:
approx 19 UK pounds (about US$30). I'll scan the arrangement and email it to
anyone who requests it. The thing that had me puzzled were the three
connections on the choke (ballast). Two of these connections were actually
I've simply mounted it all on a piece of MDF. I put the PIC (a 16C71) next
to the tube and put the whole lot in a drawer before turning it on.
I'll probably build a proper enclosure at a later date but just wanted to
get up and running quickly.
Thanks again for the help.
Robin, as others have mentioned, and I really want to emphasize this,
you can `seriously damage' your eyes by viewing the UV lights. I've seen a
lot of `hair-brained' schemes for erasing chips here but for the same price
and effort folks put into building their own erasers, you could buy a
commercial unit such as the Datarase II for around $40 or $50 with a timer.
I've been using it for several years and it is very reliable and erases up
to 4 PIC chips in under 15 mins.
At 04:34 PM 3/5/98 -0000, you wrote:
>for the same price
>and effort folks put into building their own erasers, you could buy a
>commercial unit such as the Datarase II for around $40 or $50 with a timer.
I follow threads on the subject of UV erasers (especially home-made ones)
with some interest, since I'd like to start playing with PICs other than the
EE variety. Being a bit of a cheapskate, and a bodger, I always look for
ways to make stuff rather than buy it, where there seems to be a large
difference between the cost of the parts, and the completed item. I made a
UV exposure unit for making PCBs for 10 or 15GBPounds, which wouldn't
be any use to a 'professional' but which does for me.
However (you're not supposed to start sentences with 'however', are you?);
I'd cheerfully pay 25 or 30GBP for this Datarase thing, but over here in
Merrie England, people want 50GBP ($80-odd). Rather less attractive at
that price? Especially if an amateur-capable bodge can be done for
Having said that, if any English PICers know where I can find a UV eraser
at a realistic price, please say!
|John Midgley wrote:
To make an eprom eraser, just get a set of 8-watt fluorescent-light
control gear (starter and ballast), a light-proof box, interlock switch
a 8W hard-UV tube (253.7 nM wavelength uncoated). The tube is
the same as an 8w white tube, but it emits shortwave UV. The circuit,
the light-proof-ness of the box, and the operation of the interlock sw
can be tested using a harmless white tube. Remember that shortwave UV
is biologically damaging both to the eyes and skin, so avoid exposure.
This type of UV lamp works in the shortwave UV region, the most
for erasing. This is the same as the germicidal lamps used in water
treatment, etc. Note that soft-UV tubes (used in sunbeds, etc) may
devices slowly, but not very well.
BTW, a xenon strobe can be used to erase devices. Dataman make a strobe
eraser, which works in seconds, and can be used with the device in the
programmer!. I keep meaning to build something like that myself!
BTW, I recently succeeded in erasing 150-odd mis-programmed OTP PIC's by
baking them. Think they won't be reliable, though!!!!!!
Hope this of use....
John, the Datarase II is made by the Walling Co. They have two models one
of which adds a 2-8 minute timer. I find it typically takes around 10-15
mins to erase PICs. I have been able to use shorter times but I use 15 mins
to be sure. It erases EPROMs in around 3 mins. It comes with an AC adaptor
and a `little' owner's manual that has a very good explanation of EPROMs and
UV radiation. I'm not sure about shipping costs but you can order it in the
Digikey: 800-344-4539 http://www.digikey.com
Datarase II without timer. P/N ER2. $39.95
Datarase II with timer. P/N ER3. $49.95
At 08:11 PM 3/10/98 +0000, John Midgley wrote:
>Robin wrote (Actually, I'm Tom ;-)
>>for the same price
>>and effort folks put into building their own erasers, you could buy a
>>commercial unit such as the Datarase II for around $40 or $50 with a timer.
(To Jim this is a duplicate, because my original response went directly to
him, instead of to the list. So his response came to me. Since this
information reflects what is sure to be a breakthrough in
otp-erasure-technology, (not to mention a new meaning of "burning chips"
:-) I wanted to get it back to the list. Jim--will you please re-respond?)
>BTW, I recently succeeded in erasing 150-odd mis-programmed OTP PIC's by
>baking them. Think they won't be reliable, though!!!!!!
Did you really, or are you just funnin'?
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