FAQ - So you just got/found/refound a SAM - What now?

FAQ - So you just got/found/re-found a SAM - What now?

Last Update: 25/03/2020

Social Media

Post on this forum, many people check in here or join SAM Coupe Users Group on Facebook which is where most people hang out, this is the fastest way to get advice and guidance from a friendly group of enthusiasts. 

Never mind that, I just want to sell it and make some cash

That's fine, a 10 second trawl of eBay sold items will have already told you that SAM's are quite rare and desirable.

As a courtesy to those on the scene and to get some good karma, ask for valuations and offer it on the Facebook groups SAM Coupe Users Group and/or Sinclair For Sale - ignore the crazy prices from scalpers on eBay :-)

Before you power on

Chances are you have already done this as it's in the nature of human beings, but if not here are some things to check for:

1. Check the mains plug has no loose wires and a 3A fuse (if applicable)

2. Plug in the External PSU on its own first, it should hum when operating and not exude any magic smoke :-)

3. If you have a SCART lead check that it is correct one for use with the SAM, the RGB Scart lead is non standard and has voltages exposed on certain pins which can be dangerous to your equipment.

4. Read the Sam User Manual :-)

Making things visible

Get an proper RGB Scart cable.

Regardless of what you had back in the day trying to get RF working on a modern TV is not only painful but the end result is a horrific picture and some of the older SCART cables were not SCART complaint with regards to voltage levels and signals so can leave you with a degraded picture or no picture at all.

Sources for cables are Colin Piggot/Quazar https://www.samcoupe.com/hardware.htm or Retro Computer Shack https://www.retrocomputershack.com/ 

I don't have a TV with a SCART socket

This is becoming more common, there are a number of units that can convert RGB SCART to HDMI but tend fall into two categories:

1. Cheap and laggy (can be up to 6-10 frames behind)

e.g.  https://ebay.us/ZO22F2 

2. Expensive and zero/less laggy

e.g. https://videogameperfection.com/products/open-source-scan-converter/

https://www.retrotink.com/product-page/retrotink-2x-scart 

https://solarisjapan.com/products/xrgb-mini-framemeister-compact-up-scaler-unit 

Mandatory checks & modifications

There are not many things that are mandatory to make things work per se but in order for your SAM to be useful you should have the following at the very least:

1. 512Kb of RAM i.e. the extra 256Kb module is installed.

It will say on the boot screen what is installed and almost all software apart from the very earliest will need 512Kb. 

You can make your own with schematics from Velesoft https://velesoft.speccy.cz/samcoupe_schematics-cz.htm or buy from Quazar.

2. ROM Version 3

ROM version can be ascertained by typing PRINT PEEK 15 and dividing by 10 so '30' is ROM 3.0.  If you have an earlier ROM then you may struggle with compatibility or even booting a disk.

You can burn yours onto a 27C256 32Kb PROM with any capable burner from the ROM images on this site or buy from Quazar.

3. Video Reflection fix

Even on an old CRT you can see the interference so this quick fix is essential on modern displays.

4. The External PSU may require modification.

If not already done it is recommended to swap diode D4 with a new IN5349B (12 V, 5.0 W Zener Diode Voltage Regulator) and replace diode D3 with a new IN4001 (Rectifier, 50 V, 1.0A) plus replace R3 with a new 33R/4W resistor- see External PSU Modification page.

How do I get inside?

See Disassembly and reassembly page.

What about capacitors?

A lot of older hardware was built at a cost and uses cheap/cheaper components, often electrolytic capacitors fall into this category and they can dry out/leak/bulge over time.

Anecdotally most SAM's seem to have fairly decent motherboard caps in them and do not require wholesale replacement, obviously if they are bulged, leaking or smelly then they should be replaced.

The External PSU has large smoothing caps and should be checked too.

Keyboard Issues

The keyboard is a membrane type and can fail as the plastic degrades leaving sections of keys not working, replacements are available from RWAP at https://www.sellmyretro.com/offer/details/new-sam-coupe-keyboard-membrane-2093

If you are missing keys or key posts then Quazar hold stock of these.

Disk Drives

If you want to get the disk drives working and you have one of the original blue-button Citizen drives then it is almost certain that the rubber belt has perished with age.

Check out the Sam Drive section here on belt replacement.

You will also need the clean the heads regardless of drive type, again see the Sam Drive section here guidance.

Other faults such as the inability to boot (Error 53 No DOS) or read may be down to leaky capacitors on them that will thwart you - Quazar or Mutant Caterpillar http://www.mutant-caterpillar.co.uk/shop/ can help with that if you're not keen on soldering surface mount components.

Cleaning

1. Case

Once disassembled you can remove the keyboard and clean the plastic case with just soap and water, leaving it to dry completely.

If you want to use 'Retrobrite' techniques to whiten the case then you do so at your own risk.

The base should just need a wipe with a damp cloth, any areas that are rusting should be treated/sprayed if you wish.

2. Keyboard

The keyboard will most likely be dusty, hairy and full of bits you'd rather not think about how they got there but it can be disassembled and cleaned easily.

Remove the back plate screws and make a note of how the plungers sit (a photo will help here) as they are going to drop out when the keys are removed.

The larger keys will have metal support bars, these will need to be un-hooked from the keyboard base with fine pliers to push them out of the plastic lugs.

Remove the keys by pulling upwards gently with a key puller or prying with a plastic (not metal) 'spluger' and wash them and the keyboard base n hot soapy water before allowing to dry completely.

Wipe the membrane with a damp cloth if mucky but do not use any cleaners/alcohol as this may damage the plastic.

As mentioned above the membrane will be fragile after 30 years so take care.

3. Disk Drives

As above, see the Sam Drive section for guidance.

4. PCB

If the PCB has muck on it then you can use a PCB brush (to avoid static) to clean it and then using isopropyl alcohol with a toothbrush for any stubborn areas, blotting with kitchen roll to remove the muck and repeating until the area is clean.

Make sure all the alcohol has evaporated completely before reassembly, be especially careful of socketed chips which may retain the liquid longer than the open board.

5. Ports and connectors

These wouldn't usually need attention unless they have become very dirty - a toothbrush and  isopropyl alcohol is good here with a wooden toothpick/cocktail stick to work the metal connectors very gently.

If the connectors are actually damaged or corroded then replacement is the only feasible option.

Getting Software

You can download titles that are available from this site as EDSK files on the relevant pages, or visit the NVG FTP Site. 

Mass Storage Solutions

For the gamer/casual user seriously consider getting a Gotek installed as your primary drive - Quazar sells a suitable interface to make it plug-and-play.

For advanced users there is the Atom or Trinity Ethernet Interface.

And Finally...

Update the Serial Numbers page and add a person page for yourself on this site :-)