Synclavier HOP Hand Operated Processor + D0I interface card

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via this auction

One of the pics looks very close to this listing from 2015. Similar description as well, but updated.

"Note: Perfect condition, tested today and working perfectly, no broken switches. I've checked this over 10/2/2020 and tested it with a Synclavier II mini-system, all the switches are working properly and everything has tested good. There are absolutely NO scratches or scuffs on this one. It is absolutely as new.

Absolute mint condition, see the photos, it is stunning.

This listing includes the HOP control panel box with built-in cable, interface card to plug into the computer bin of the Synclavier, and an anti-static protective bag to hold the card when not installed in a slot.

The rarest and most sought after piece of Synclavier hardware is the HOP hand-operated processor. Originally designed for internal company use debugging new software and designing new interface cards, it later proved to be indispensable for anyone trying to maintain Synclaviers and troubleshoot Synclavier problems. Any Synclavier technician must have one of these at all times. TRY2FIND1.

The Synclavier HOP Hand Operated Processor consists of a control panel of switches and LEDs connected by a cable to an interface card that plugs into the computer bin of any NED system (Synclavier II, Synclavier PSMT, Synclavier 3200-6400-9600, Direct-to-Disk, PostPro, etc.). It is an incredibly rare and useful item that was generally not available for sale to customers, as it involved the proprietary aspects of NED service, but some larger studios wouldn't own any gear their in-house techs could not fix, so NED offered them very high priced training and the HOP to use for diagnostics. Almost any HOP in existence (maybe 30-60 of them?) came from an NED tech.

NED actually promoted these as part of the system in the 70s when they (as NEDCO) were trying (unsuccessfully) to sell the Synclavier without the keyboard and synthesizers as a general purpose mini-computer system (ABLE/20, ABLE/40, etc.) for industry and science. It was originally designed by NED for NED, for use in software debugging.

The switches and LEDs allow the user to read data from and write data to any of the three buses in the Synclavier ABLE computer (data bus, memory bus, and device address bus). You can set up an opcode (assembly language command) on the switches (in hexadecimal), then deposit it on the bus, and the system will perform the command you just gave it, like programming software in real time with your fingers. The Synclavier HOP can halt the system at any time, you can insert commands then, then resume CPU operation with the Synclavier executing that command.

The Synclavier HOP can also use the LEDs to give you a readout of what the system is doing. Company users quickly figured out that it can be used for diagnostics, because whenever the system crashes, it will hang at that point, and the device address bus will be showing you the last device address it was looking at when it crashed.

For example, if a system is crashing sometimes, the HOP can be plugged in and it will be a flutter of lights, just a solid matrix of red LEDs that all appear to be on because they are strobing so rapidly, until it crashes again, then it will hang, for example, showing "164" in hexadecimal on the lower row of LEDs.

This would mean that the computer was reading or writing to device address 164 at the time it crashed, and that means the D164 card that connects to the keyboard.

Therefore, this saves us a lot of time by telling us that the D164 or something connected to it (in this case, the keyboard) is causing a problem.

Without the HOP, we'd have to swap out 15-20 cards (or up to five times that many if the faulty card is in one of the other bins that is connected to the computer bin) one at a time before we found a bad D164.

This is why all Synclavier techs have used these to save time, and why these are very sought after.

You might have seen this item in the photos I take of my system builds in progress, this is because I keep one installed for the entire time a system is here, to monitor any crash activity and find any potential problems before shipping a system to a client. Some of the few people who have them leave theirs connected all the time just to look at the lights.

I never go to a service call without one.

Using this hardware is always the first step to take in trying to start a dead Synclavier system that has been sitting unused for many years, and even more so for a Synclavier II to that does not have a Macintosh or terminal display (in which case you could have NO idea what is going on inside the box, if anything is happening at all).

The light activity on the LED panel always assists me greatly in knowing what the floppy drive is doing, what the Winchester drive is doing, and what brain activity there is going on inside the system, if any at all. That first view often leads me to give attention to some physical piece of hardware, such as physical connections, looking for broken wires, loose or corroded connectors, or power supply issues.

The immediate information given is often the most helpful. A very common problem with PSMTs (and PSSs and PSTs) and Synclavier IIs that have been sitting unused for years is a dead +5v power supply. There are anywhere from two to six of the same +5v supplies in there, and they are often dead by now. The HOP will instantly point out that the CPU power supply is dead (no LEDs come on at all when the system is powered on), so I will know to check it and replace it from the Synhouse stock if necessary.

Beyond that, the HOP gives me the crash codes so I know what card might be causing the problem and should be swapped as the next step and getting the system going again.

If someone comes to hire me to fix a dead system from far away, if they have one of these units there, it can provide me with a lot more information remotely, possibly preventing the need to ship the system to Los Angeles for a hands-on repair, and I can just ship them the needed new card or power supply instead, saving them a lot of money.

One of the photos shows the unit and the built-in cable and the interface card and user manual, and the other photo shows the way the unit is actually used, with the interface card inserted in an empty slot in the computer bin of an upgraded Synclavier II.

Also included is the photocopied company user manual that lists the device codes to tell you what piece of hardware the malfunctioning system is crashing to. The manual is even more rare than the hardware!

The bad news? The Synclav com Synclavier shown in the photo is not included, it is for display purposes only.

I'll be listing a New England Digital sound library with a SCSI hard drive within a few days."