|★ HARDWARE ★ MONTAGES ★ CPC 6128 Plus - Tape Upgrade (3/3)|Amstrad Action) ★|
|CPC 6128 Plus - Tape Upgrade|Amstrad Action)||Hardware Montages|
You've been waiting patiently for ages, and now it's here.
In the final part of our upgrades series, Phil Craven shows you how to fit a tape connector to your 6128 Plus.
For some peculiar reason Amstrad, in their not so infinite wisdom, contrived to produce the excellent 6128 Plus computer complete with everything needed to access a tape recorder -except a connector. Well, almost everything. The software is inside the system cartridge. You can see it by typing |TAPE[ret] followed by CAT[ret) or RUN"[ret]. The tracks and holes for the tape components are already on the circuit board and all that's missing is a transistor, a resistor, and, of course, that connector. The additional cost of including them would have been so tiny and their function so useful that no one can fathom why they were left out. But that's Amstrad, I guess.
Anyway, we can put it right by adding the tape facility for a mere £10 which is a massive saving of more than £25 over one available tape upgrade and £8 over Avatar's diy kit. Installing it is incredibly easy and results in a neat 5 pin DIN tape socket mounted in the back of the computer. The ability of the computer to start and stop the tape recorder is included - that's the infamous ‘remote' facility that some tape upgrades
Cheap and nasty tape recorders, with the volume turned up high, are best for computer use. Data recorders are useless for music and voice but are ideal for computers.
Are you sitting comfortably?
When handling the circuit board try to avoid touching any of the circuitry. In the old days some types of chips could be zapped by the body's static electricity and, although this is less likely now, it's better to err on the side of caution so, before opening up the computer, hold the cold water tap for a second or so to discharge any static.
Open the box one more time...
Disconnect the computer from the monitor and remove the cartridge. Turn it over and take out the six screws from the underside. While it is upside down, notice the three catches that hold the case top to the case bottom. Turn the computer the right way up again and undo those catches by pulling them outwards.
Undo the wires
Lift the top up and back and disconnect the two pairs of wires that join the case top to the circuit board. Take note of their colour codes so that, when finished, you re-connect the correct pair of wires to the correct circuit board connector. Slip the keyboard's slide-in film connectors out of their sockets and remove the keyboard. Disconnect the 4 way power socket and 26 way signal cable from the disc drive - not from the circuit board. Take out the three screws that hold the circuit board to the base and lift the circuit board out altogether.
Look and learn
Fig.1 shows the positions of where resistor R4, transistor Q01 and connector CP07 would have been if Amstrad had fitted them. They are clearly marked on the circuit board but their holes are filled with solder. It's your job to clear the holes and fit the parts.
Suck 'em and see
A solder sucker costs about £3 -£4 from Tandys or Maplins but it seems a shame to buy one just for 13 holes so, if you haven't already got one, or if you can't borrow one, you could try working the parts into the holes by using a soldering iron to melt the solder in each hole, one at a time, and easing the parts in bit by bit.
The resistor and transistor shouldn't be too difficult but the 8 pin header strip (set of pins) might be not be so easy. Only five of the pins are actually needed so pulling the other three out with a pair of pliers will help. Failing that, a solder sucker is the thing to get.
Solder the resistor, R4, transistor, Q01 and the 8 pin header strip into place. The resistor can be fitted any way round as can the header strip but the transistor's flat side must be positioned to match the white, flat sided, transistor shape printed on the circuit board. When those three parts are fitted, the circuit board can be screwed back onto the case bottom, the disc drive connectors re-connected, the keyboard put back and its film connectors re-connected. The copper leaf springs should rest on the underside of the keyboard. If they've been bent down, bend them back up again.
The cable assembly
This comprises a 5 pin DIN socket, a relay with diode for the remote facility, a foot or so of 5 way multicoloured ribbon cable leading into an 8 way terminal housing to push onto the 8 way header strip now fitted.
It can be made with the relay and diode in any position along the cable but Avatar's arrangement is ideal and keeps any metal parts from touching anything where short circuits might occur so that's the arrangement we'll use. The more I say, the more it seems there's no end to my pinching of other people's ideas so, before the complaints start, I'd better own up. Most of the CPC's hardware add-ons, including the upgrade kits, are owned and made by me and I'm simply sharing with you what's already mine.
Sounds very tinny
With a Stanley knife or similar, cut between and separate each strand of the ribbon cable to about 1.5” to 2” at both ends. Strip away about 0.25” of insulation and tin each of the 10 ends. Tinning is melting solder over the bare wire by holding the wire onto the soldering iron tip and putting solder onto it. It coats the wire with solder to make more reliable soldered joints but it isn't necessary for components like those you've already fitted.
I'm afraid it's terminal
Solder a terminal onto each of the five strands at one end of the cable by melting solder into the solder end of each terminal and then melting it again whilst a tinned strand is held in it. You'll need a spare hand to hold each terminal for that job so how about making some imaginative use of a bit of sticky tape? Stick the terminals' nort-solder ends to the tape to prevent them from moving. The terminals will later push into the white terminal housing but not yet.
Prepare the relay (silver cube thing) by cutting off the unwanted pins and shortening the two pins where the diode is to be soldered down to about 0.25". The relay has a small tongue along one side which must be used to identify which pins to cut off, which to shorten and which to keep anyway. Fig.2 shows exactly which pins to cut.
You should be left with two long pins and two short ones (one of them next to the tongue and the other opposite it). Bend the diode's two wires at right angles to the diode's body and cut them back to about 0.25”.
A small vice would help with this next bit. With the relay held securely, pins pointing up, solder the diodes wires to the relay's two shorter pins making sure that the diode's wires don't end up touching the relay's surface. The diode gets hot during this and is best held with pliers. For neatness, you can bend the wires in and the pins out so that they are parallel to each other. You can also bend the two long pins out of the way.
It is very important that the diode is soldered the right way round. It has a white ring at one end which must be soldered to the pin that is opposite the relay's tongue and not the pin that is next to the tongue. Fig.2 shows how it should be fitted.
The relay can now be connected to the DIN socket by its long pins. Run some solder over the DIN socket's five main tags. Cut about 0.25'' off each of the relay's two long pins, splay them outwards and solder them to the DIN socket's tags as shown in fig.4. It doesn't matter which pin goes to which of the two tags as long as one pin goes to each of the two tags shown. Personally, I do it so that the diode, which now faces the DIN socket, sits neatly inside the semicircle of tags but then I fill the gaps with hot glue to ensure that the pins don't touch any tags. You might find it better to position the diode outside the semi-circle of tags. Wether inside or outside the tags, you should note that a hole, the size of the DIN sockets barrel has to be drilled in the case top and the whole assembly pushed through it so keep the overall circumference inside the barrel size. The gap between the DIN socket's black base and the relay's base should be about 0.5" to keep it from touching the disc drive when fitted.
Are we nearly there?
We're nearly there. Just the cable to solder up. Solder the cable's coloured strands, the ends without the terminals, to the relay/diode and DIN tags as shown in fig.2. It isn't important which colour strand is soldered to which tag or end of diode as long as the terminals are inserted into the correct positions in the white housing. To be safe, though, stick to the colours as shown.
All together now
Three holes for the DIN socket's barrel and two bolts need to be drilled into the computer's case top. Fig.1 shows a good place to do it. Push the cable assembly through the large hole and bolt the DIN socket into place. Now the terminals can be pushed into the housing. See fig.1 for the correct positions with respect to the housing's two small feet. Each terminal has a small leaf spring on one side and the housing has a set of small windows. Push the terminals in so that the leaf springs pop into the windows. If you manage to put a terminal into the wrong place, push down inside the window with a screwdriver, to release the spring catch, and puil it out.
You can now re-connect the two pairs of wires from the case top to the circuit board, push the new tape connector onto CP07, making sure that the small feet are positioned according to fig.6 and completely put the computer back together.
Note that fig.1 shows the signals that are connected to the DIN socket as seen from the tag side and not from the more usual holes side. A suitable cable for your particular recorder can be obtained from that information.
You computer will still power up with the disc drive as default. |TAPE changes the default to tape until you type |DISC or reset the computer. I is obtained by typing SHIFT and @ simultaneously. Having typed HOPE, any program you wish to run will be met with the on-screen message, Press play and ana key... Pressing play on the tape recorder should not start the tape turning because the computer is in control of its motor. After pressing any key the computei starts the tape's motor and stops it again when the program has loaded.
The main purpose for having a tape facility or a disc drive computer is to save money by buying tape software and transferring it to disc. The problem with most such software, particularly games, is that they are protected against copying and a tape to disc transfer utility is usually needed. Both software and hardware types are available from advertisers in this issue but it is beyond the scope of this project to discuss them further.