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Friday, 04-Feb-2022 03:58:43 GMT
Z88 Hardware
EPROM Erasers
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Universal Power Supply
Key points
- Input voltage 90-264
VAC
- Input frequency 47-63
Hz
- Overcurrent protection
All outputs protected to short circuit condition
- Operating temperature
0°C to +70°C, derate linearly above 40°C to 50% @
70°C
- MTBF 100,000 hours
minimum at full load at 25°C ambient
- EMI requirements
Meets conduction limits of (a) FCC PART 15 CLASS B (b) CISPR
CLASS B
- Safety Approvals
UL/cUL60950, TUV/GS (EN60950)
- Size 91mm x 36mm
x 38mm (3.6" x 1.4" x 1.5")
Overview
At last a small lightweight
power supply for your Z88.
The Z88 does
not physically switch to the power supply when being powered
externally. Power from the internal batteries will only be saved if
this power supply is used.The reason behind this is the Z88 runs on 6v, ( 4 x AA 1.5v batteries).
A diode is used in the external supply circuit which drops the voltage
by 0.8v. If the normal 6.5v Z88 Mains adapter is used for example, the
voltage across the batteries will be
6.5 – 0.8 = 5.8v.
The
batteries in the Z88 will be discharging until they reach 5.8v. This is
about half their charge. The Universal Power Supply has an output
voltage of 7v. This gives 6.2v across the batteries which ensures that they hold their charge.
When the Z88 came out
the Mains adapters were built using large and heavy transformers,
forcing users to either leave them at home or having two supplies,
one for home and the other at work. This power supply is
the modern lightweight equivalent .
Use it either in the
USA, Europe or anywhere in the world.
Note: LOW STOCK - will be discontinued
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Ram
Packs |
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Using Ram Packs
with your Z88.
Inserting the RAM
pack into Slot 1 of the Z88
The Z88 comes with
32K RAM 'built-in' memory. This is used both as working memory
and for storing files.
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The Z88's memory can
be expanded in 32K, 128K or 1M byte blocks by inserting a RAM
Pack.
A 1M RAM Pack has
enough room for around 200 typed A4 pages.
If power is lost,
through the batteries going flat or if an application crashes,
any files that or stored in RAM or unsaved current work may be
lost.
Cambridge
Computer The Z88 Card Exchange System (864K) Cambridge
Computer Memory Card booklet (500K) |
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1M Low Power RAM Card
This uses a modern static RAM chip which gives the following advantages:-
- 1M RAM
- Low Power
- Longer battery life.
This is a RAM
pack.
If removed, a HARD reset is required
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EPROM Erasers
EPROM
Erasers |
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The Z88 is only able to write
or read to or from an EPROM pack. When you save the same file
twice, the Z88 only marks the old file as being deleted, it does
not reclaim the space back. The EPROM Eraser allows you to clear
the EPROM, to remove all the files, so that it can be used again.
The EPROM pack has
a hole to expose the window on the EPROM device inside the pack
to allow the light from the eraser to erase the EPROM. The EPROM
pack is pushed right into the eraser to turn on the light and
erase the pack.
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EPROM Erasers formats
EPROMs allowing them to be used again. Unlike disks, individual
files cannot be erased.
Mains operated (240v
AC) it has a 20 minute timer to erase the EPROM pack whatever
the size.
We have reduced the
price of this item due to the arrival of the Flash EPROM!
You can use this to
erase ordinary EPROMs provided you make a carrier 2" wide
to place the EPROM into the eraser instead of using an EPROM
pack.
The
bulbs for the old and new style EPROM Erasers are no longer available,
but then at these prices - who cares?
Cambridge
Computer EPROM Eraser Instructions (946K)
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Additional Information
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Capacity |
27xx
EPROMs 24-28 pin |
UV
Intensity: |
Unknown |
Board
area: |
50mm
x 50mm 2" x 2" |
Timer: |
20
min. |
Indicators: |
LED |
Weight |
160g |
Dimensions |
57h
x 87w x 83d mm |
Power |
230
v No mains plug fitted |
UV
Tube |
Not
replaceable - uses special UV QUARTZ bulb |
Timer Board
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ELREMCO 406/003
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Chip used
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MC14060BCP 14-Bit Binary Counter and Oscillator
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Is
there any other way to erase an EPROM ?
The following suggestions
have been made.
- I usually leave mine
on the window sill for a while (to let the sun do its work).
This can take some time in the winter, but get a few high UV
days this time of year and you're laughing.
- What about a tanning
lamp, or one of those children's spy pens (writes invisibly until
you illuminate with a UV source in the end of the pen - can be
bought for £1!).
- I tried that once
and found that the lamp also melted the EPROM case. When I finally
got the EPROM out I discovered that the files had not been erased
at all.
- There is a particular
frequency in the UV spectrum that erases the EPROM. - Yep, you
need a high-
intensity UV source of wavelength 253.7nm. There's a DIY project I keep on meaning to try.
- It uses a germicidal
uv fluorescent tube, which (as you might have guessed) is not
something you want to expose yourself to!
- A lot of modern filters
in garden ponds use these tubes, so if you have a friend who
has fish try popping the EPROM inside the filter enclosure for
a bit :-)
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- The tanning lamp
I used certainly wasn’t on the right frequency but it did
get me ‘browned off.’
- When the Z88 User
Club was running they offered a service to erase EPROM for £5
each.
We can offer that service if you want but in the long run it
doesn’t help and here is the reason why.
Z88 User
- Umm – I’ve
got a lot of files on my Z88, I should really back them up onto
my EPROM just in case the Z88 looses them.
- I’ve got a 128K
EPROM pack; I could put them on there.
- I don’t really
want to fill it up because I haven’t got an EPROM eraser.
- Oh bother –
my Z88 has just crashed – I’ve lost all my files.
So the moral of the
story is
If you want to use the EPROM packs please invest in the EPROM
eraser, otherwise you will not use the EPROM and the benefit
you would have will not be realised. The only exception to this
is if you are using the EPROM to store Applications, then having
an EPROM eraser is not so critical.
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Z88
Hardware
Description |
Price |
VAT |
Total |
Cable - Printer (Parallel) |
£34.00 |
£6.80 |
£40.80 |
Cable - Printer
(Serial) |
£5.00 |
£1.00 |
£6.00 |
Card Case
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£6.66
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£1.33
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£8.00
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Card Case (machine screws and nuts only (4 or 2)
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£4.00
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£1.00
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£5.00
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Carrying case |
£6.95 |
£1.39 |
£8.34 |
Flash EPROM (1M) |
£45.83 |
£9.17 |
£55.00 |
Flash EPROM (1M) LED Upgrade
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£15.00
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£3.00
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£18.00 |
Flash EPROM (512K) / 512K RAM
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£49.17 |
£9.83 |
£59.00 |
EPROM
Card (32K)
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£16.67
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£3.33
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£20.00
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EPROM Eraser |
NONE LEFT |
EPROM Card (128K) |
£25.00 |
£5.00 |
£30.00 |
EPROM Card (256K) |
£49.17 |
£9.83 |
£59.00 |
Keyboard
|
£20.00
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£4.00
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£24.00
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Keyboard Membrane
|
£20.83
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£4.16
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£25.00
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Mains Adapter (220v) |
£8.95 |
£1.79 |
£10.74 |
Modem 300/1200-software & cable |
£25.00 |
£5.00 |
£30.00 |
Modem |
£10.00 |
£2.00 |
£12.00 |
Power Supply (90-264v)
Note: LOW STOCK - will be discontinued |
£30.00 |
£6.00 |
£36.00 |
RAM
pack (1M) (low power)
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£49.16
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£9.84
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£59.00
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RAM pack (1M) (CC)
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£40.83 |
£8.17 |
£49.00 |
RAM pack (512K) |
£37.50 |
£7.50 |
£45.00 |
RAM pack (128K) |
£20.83 |
£4.17 |
£25.00 |
Topper - Heavy Duty Version Out of Stock |
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©
Rakewell Limited 1998 - 2021
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Company Details
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