Once upon a time there were Service Manuals

Piing

Piing

Axe-Master
I've found the Service Manual of the Roland VG-8. That was a real Service Manual! like the old time TVs

It starts with the part numbers of all the mechanical components, including an exploded view

A block diagram of the circuit with a description of the functions of each block

Exhaustive parts list of all the components, from washers and screws to IC references

Step by step "Test Mode" diagnose. It can actually tell you which IC is faulty

Troubleshooting logic tree

PCB assembly and wiring diagrams

Internal wiring diagrams

It is interesting to watch

(you may need to install this Adobe Acrobat Reader extension if you do not have Asian fonts. It is bilingual)
 

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  • VG8EX Service Notes.pdf
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Yeah,

That was back before changes were implemented so fast, the manuals couldn't keep up! (also manufacturers realised they could save some money, and consumers lowered their expectations).
I used to have a case full of manuals I'd cart around when fixing stuff.... Now, a decent manual is really hard to find, and if something screws up you either replace the whole unit, or circuit board!
Thanks
Pauly
 
Stratman68 said:
Good ole days indeed! I still have mine for my Boss GX700............
Click to expand...

The GX-700 is interesting too. The diagnose mode can even generate different waveforms to analyze with a scope

I note that it has a BL02RN2 ferrite bead at the front input, for high-freq noise suppression. That is interesting.

The VG-99 also came with a external ferrite clamp to attach to the input cable

GX-700.png

Murata BL02RN2-R62 Radial Ferrite Bead Inductor.png
 
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Yes, L2is the ferrite bead.

BTW. Here is the Roland patent of the "imaginary pickup disposed at an specific position". I've always been impressed by the realism of their pickup position simulation.

Now I understand why it is so important to accurately specify the distance from the saddle/string contact point to the hex-pickup for each individual string.
 

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It used to be that there were local retail stores that sold electronic parts too, from Radio Shack consumer crap to real stuff like at Active Electronics. Most of that's gone now, not like covid-era gone, way before that.

So who needs a manual for anything?
 
Sadly many things are also not really designed to be repaired easily anymore. When's the last time you saw an electronics or appliance repair shop? People just throw them out and get a new one if it's out of warranty. It's an unfortunate side effect of progress, with products getting increasingly complex yet cheaper and cheaper. Take something "simple" like a blender. Years ago it was nothing but an electric motor and some simple switches. Now there's PCBs with microcontrollers for a ton of modes and functions, touchscreens or capacitive control panels, LCD displays, etc. For a great many products out there, it's often no longer cost effective to repair them. Factoring in parts and skilled labor, repair costs can often exceed the purchase price. Couple that with many people's constant desire to always have the latest and greatest toys and product turn over is crazy fast for so many things. There's more money to be made is selling you the next model than keeping the old one going. Economies of scale benefit the manufacturer way more than the repair shop.

For the determined out there among us, there's still some good resources out there. Most have transitioned to online. Here in the US, sites like Mouser and Digikey are like electronics nerds candy stores. McMaster Carr is awesome for hardware and tooling.

It's true though that in this age of IP and patent trolls, companies are often pretty reluctant to release detailed repair info to anything other than "authorized" repair facilities. Fortunately there's a good amount of info out there online for a lot of vintage gear.
 
Surface mount tech has made repairs that are simple in principle difficult or impossible for most folks. I've modified, designed and built both analog and digital devices, and I wouldn't touch it. Maybe I'm a coward, but damn, that's a lot of leads really really close together.
 
Dave Merrill said:
Surface mount tech has made repairs that are simple in principle difficult or impossible for most folks. I've modified, designed and built both analog and digital devices, and I wouldn't touch it. Maybe I'm a coward, but damn, that's a lot of leads really really close together.
Click to expand...
It's not that bad if you have the right equipment and knowledge. Depends on the size of the components, but some things can be easier to repair than thru-hole. To swap an SMT component you just need to heat it up a bit and then you can literally wipe it off the board. No trying to dislodge a thru-hole part (especially a pain for multi-pin ICs). Pretty much everything we make at Intellijel is SMT with the exception of the panel components and LEDs and our techs are able to fix it (and we've had other techs be able to repair it when sent instructions).

I've built quite a few SMT DIY synth modules and in many cases it was faster than the equivalent thru-hole because there was no stuffing of components, flipping the board over, clipping leads, etc.
 
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