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JTV-89F newbie modeling confusion/problem?

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A black import JTV-89F bought from eBay was received in seemingly good condition 2 days ago.

Monkey reports flash version 2.10 (2:33 was tried and seems to behave identically).

Pressing model (or tuning) knob seems to have no effect, and I have yet to notice any LED illuminating.

Really, unclear what to expect; should  an active model name on the knob be backlit? 


Yesterday, Workbench HD somehow provoked the JTV-89F into Variax mode (no LED noted),

and blending worked between magnetic and model sounds from both 1/4 phone and VDI connections,

but model output has not yet been achievable again today..


I try combinations of battery or VDI power

and VDI connection via USB dongle or HD500, with and without 1/4 phone

(which seems necessary when using battery with USB dongle).


What am I missing?

* Is there no explicit way to force model output using Workbench HD?

* Is there a video that clearly demonstrates JTV-89F model/Variax mode switching?




On a semi-unrelated note, why does Workbench HD Read Me 

for version 2.14 continue warning to use it only with the USB dongle?

I read that there were problems with older code versions, but

audio gets buzz/ticks when rotating either JTV-89F volume or tone control

when VDI is connected to the USB dongle, and NOT when connected to my HD500;

yesterday's modeling success occurred while running Workbench HD via HD500..??


Prior to that, I also had issues getting Monkey up to version 1.78 on macOS 10.13.6;

perhaps Windows users have it easier.

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OK, I found an article which declares this is/was a fairly common problem:

Fixing a faulty Variax model selector


Removing the model knob and pressing its shaft woke modeling and the LED, >>after releasing<<.

A dab of hot glue stuffed into that knob cavity qualifies as a cure.


Removing the knob for tuning, with seemingly the same LED lashup,

 and pressing its shaft did nothing obvious,

but >>turning it<< illuminates that LED, but >>only briefly<<;

too bad this is both unintuitive and undocumented..

Edited by blekenbleu
healed myself after more research

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Workbench can work thru an HD500, but an HD500 won't do Flash updates, 

you need the interface device a RJ45 cable accessories.



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Oops, I used the HD500 with Monkey to revert Variax from 2.33 back to 2.10 .. seems OK.


Thanks for the warning;   can that interface device also work with a Variax 300?

I lack an original USB interface for that older Variax.


FWIW,  a JTF-89 model can be tweaked to make single string tones indistinguishable from magnetic,

at least to me..  Dialing up alternate tunings is a blast!

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