Tools of the Trade
These are items that every arcade fan should, and likely will, have readily available.
- Soldering Iron - with as fine a tip as possible
- Solder Sucker/Desoldering Braid - this makes removing items from boards that much easier
Basic Board Repair Tools
These are items which are fairly essential to the board repair process; and you will find the potential scope of your repairs somewhat limited without them.
- Multimeter - if you are buying one, ensure it has a beeper for continuity testing. Checking tracks is hard enough without having to look up at the meter screen every time to see if you have a connection. If it beeps, its good and you can move on. Until recently, the ultra-cheap multimeters didn't have this audible feature, but reasonable meter's including this feature can now be had from eBay for as little as 6GBP at the time of writing (2010). The symbol for audible continuity on a meter is usually represented by the diode symbol plus a small picture of a speaker.
- Logic Probe - this sounds daunting and expensive but really isn't. It connects to the power-supply you are feeding the board with and the LEDs on the probe will tell you if the probed pin is high/low/or flipping between the two. A floating pin will show up as nothing, neither high nor low; on some chips this is normal, in other places it’s a fault. See more in the Logic Probe Guide.
- EPROM Programmer - one that can test TTLs and SRAM is very useful. Checking ROMs is essential to prove you are not trying to find a hardware fault when the issue is bad software.
- ROM Puller - these are inverted U-shaped bits of sprung metal with little inward facing lugs at the end of the legs, and are supposed to ensure chips are pulled straight out of sockets without bending/breaking pins. You hook them under the chip and pull upwards, but balancing the force applied is often difficult and sometimes one end of the chip springs out and the other end suffers from lots of bent pins. Some people swear by these, but if you have concerns then a viable alternative that finds favour with a lot of our techy friends is to use a small flat-headed screwdriver to "lever" the chips out a little at a time at each end until they chip is out of its socket. Unfortunately this too has it's pitfalls in that it is easy to accidentally gouge the board underneath the chip with your screwdriver, potentially cutting traces. No-one said this would be straight-forward... Your choice!
Advanced Board Repair Tools
These are items which are by no means essential (or in some instances even necessary) for successful board repair, however they are highly valued additions to the tool-set that can make your life easier in the long run.
- Oscilloscope - These are used to display the waveform of a signal on a screen for the user to view. Whilst logic probes are cheap and useful; if a pin is active you have no idea what the signal looks like without an Oscilloscope. Duff RAM chips often remain active but the signals are utterly mashed, easy to spot with a scope, impossible with a logic probe. All a logic probe can tell you is if the chip is totally dead or not, but unfortunately most RAM chips struggle on so without an oscilloscope you are left with the blanket replace and retry option. (Using an Oscilloscope)
- Desoldering Station - This makes getting chips off boards a breeze, its good to be able to check a chip is ok once it’s off the board so not having to cut its legs off is a bonus! This also means you are less likely to roast the chip you want to use as you take it off a scrap board to re-use elsewhere. See our Desoldering Guide for further insight.
- Logic Comparator - This is a "poor man's logic analyser" but achieves much the same goal. You give it a known good chip and clip it onto the suspect chip on the board, then it compares the outputs of the onboard chip to the test chip when given the same inputs – any differences get flagged up.
- Logic Analyser - A Logic Analyser will rarely provide any epiphany-style break-through when trying to identify a fault; but the LA helps to confirm what you already suspect e.g. you're getting decent signals on /E for a 139 but not the proper outputs.
- ESR Meter - Similar to a multimeter, but used to measure Equivalent Series Resistance (ESR). This useful gadget will not only let you spot the bad electrolytic caps, it also allows you to use caps from scrap or smashed TV PCBs which you can test as being fine (or not!).
The below items are the sort of items you may require to fix some of the problems you may across during your repair attempts.
As there is no knowing what will be needed and when, it may be worth just ordering what you need in an as and when basis, though this delay can be frustrating if you want to get on and fix the board ASAP!
- Solder - For soldering!
- Kynar Wrap Wire - This is extremely thin single core wire and can be used to repair traces or replace broken chip legs.
- Trace Pen - Essentially a conductive paint pen that can be used to redraw broken traces.
- Flux - This is used during soldering. It is acidic, so when applied to a surface you wish to solder to, it removes any oxidization in place, leaving a good clean surface to solder to. Additionally, flux allows solder to flow easily on the working piece rather than forming beads as it would otherwise.
A Note on Buying Equipment
Much like game boards themselves many of the items used in their repair, such as Oscilloscopes, have been in production for many years. As such, they are often available on eBay and bargains can be had if you know what you are looking for.
One thing to take advantage of is the general public's general stupidity in that they often fail to do something as basic as check their spelling!
Be sure and search the listings for:
- Oscilloscope (correct)
etc. You get the idea. Hopefully you'll stumble across a gem such as a badly listed Tektronix 'scope with lots of nice accessories which no-one else will be bidding for!
Naturally the same applied to everything (e.g. analyser/analyzer), but you are more likely to turn up a hit on items with complicated names. Give it a go.
Caution: Whilst old equipment can be a bargain, it is usually wise to choose en example from a company that is still active and/or well respected in their field. For Oscilloscopes and Logic Analysers, you're talking Tektronix, Hewlett Packard and Fluke. This way, you still have a company able to calibrate and service your device, plus they usually still sell compatible probes etc. Buying a cheap item from a long dead company may prove to be a false economy!
If you are unsure of what to buy, a good rule of thumb is to ask on the various forums where techy types hang out (UKVAC, Aussie Arcade, Arcade Otaku) and hopefully someone will advise!