Jump to content
jayhartigan

Lectrosonics ISO9VOLT Failure

Recommended Posts

I'm having trouble with a couple of these battery eliminators. Plugged into a CH-12 wall wort they meter at 8.9V. When plugged into the UM transmitter they don't even fire the LEDs. I received one that I bought used and it was DOA. I pulled another one from my kit and the UM worked. I pulled another one to test the first and then it too was DOA. I'm stumped. I think something caused this to occur quickly. One on them went from working to not, suddenly.

 

These are not cheap ($157) and I'd rather tinker with it or send it but the financial crossover is obvious.

 

Anyone have any ideas?  Any Lectro fanatics on today?

Share this post


Link to post
Share on other sites

Hi Jay,

I assume we are talking about 3 ISO9VOLTS: One that was DOA, a second from your kit that worked and still works, and a third  from your kit that became DOA. It does seem odd.

 

The units are protected by current limited input and output regulators as well as a protection diode and a re-setting fuse. Have you checked the CH-12 voltage? If you had a ~100 Ohm resistor you could check the output voltage of all of the devices including the CH-12 with a 90 mA load across the terminals. A half Watt resistor would be fine for a short period current test. A one Watt or greater for an indefinite time. The ISO9Volt is rated for 200 mA and the CH-12 is rated for 300 mA so the 100 Ohm load would be in the middle of their current range. One more question: what do all the devices read now as far as your voltmeter? Are they completely dead now? If the dead units read 0 Volts or very low, the 100 Ohm load is superfluous. 

 

i also wonder if the ISO9VOLT terminals are not making contact in the UM400 or the CH-12 plug is not playing nicely with the ISO9VOLT. The resistor test could confirm that the problem is outside the ISO9VOLT. The problem with the Volt meter, is leakage currents can give you a reading when the device is only providing micro Amps of current but dies under load.

 

Best Regards,

Larry Fisher

Share this post


Link to post
Share on other sites

Larry,

 

thanks for jumping in. Your last paragraph states my fear. Under load it dies. 

Tomorrow I will take your advice and try to find a resistor that will create a load and see how this little circuit behaves. With the loss of RadioShack it’s getting more difficult to find these parts. I’m hoping Micro Center offer such resistors. 

 

I am using two different UM 400s in this test and they both react the same for the good battery eliminator and the dead one.

 

Of the two ISO9Volt units that I’ve owned for years, one has always worked in the various UM’s I stick them into. One died for a few hours today then came back to life. It appears the resetting fuse did it’s job. What is the the duration for this fuse to reset customarily? 
 

A third ISO9VOLT that I just recently bought used with a UM400 hasn’t worked since I pulled it from the reused Lectrosonics shipping package. The owner, a respected mixer in Canada assures  me it worked for him. It reads 8.89V across the snap pins from either a BDS with a fresh battery reading 16.2V, or a CH12 sending 18.94V. 
 

Share this post


Link to post
Share on other sites

Hi Jay,

Amazon has a 200 piece metal film 1 Watt kit for $9.95. Might be cheaper than driving around. And you'll have 199 resistors for future projects.

https://smile.amazon.com/WINGONEER-200PCS-Resistors-Assorted-Values/dp/B06XSHMYP4/ref=sr_1_3?crid=3HJ0OVMNM3BE6&keywords=1+watt+resistor+kit&qid=1574080255&sprefix=1+watt+resistors+kit%2Caps%2C196&sr=8-3

 

The re-settable fuse takes less than a minute to cool down and return to 70% of capacity. A few hours and it is back to 100%. In your case, since the transmitter should pull much less than the rated current value, it will take less than a minute.

Best Regards,

Larry Fisher

 

Share this post


Link to post
Share on other sites

Jay, It's been 20 years since I looked at one of those units and I've forgotten what holds it together. Call and ask for Dean Slotness at 800 821-1121 or dean.slotness@lectrosonics.com.  I'm thinking the fibreglass cover is held on with a dab of glue.

 

Also, something I forgot to mention is that if the polyfuse "trips", even a small current flow, i.e., a normal load, it will stay tripped until it is totally powered down for a minute or so.

Best Regards,

Larry Fisher

Share this post


Link to post
Share on other sites

Also, I seem to dimly remember a flush flathead screw that holds the fiberglass sleeve to the internal PCB. But it's pretty dim.

LEF

Share this post


Link to post
Share on other sites

Hi Jay,

If it were sent to Lecto that repair versus replace comparison is certainly true. There is paperwork to get it into the system, the repair bench capital costs, the tech's time and paperwork to get it shipped. Those cost more than any parts on that simple board. However, if you can get it opened, you could look for simple failures like cracked copper traces or broken solder joints around the input and output connectors. Your time and paperwork is much less than Lectro's. And you don't have to ship it to yourself. I'll ask Dean how it comes apart.

Best Regards,

Larry Fisher

 

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...