In the shop collection are about 20 complete ENi PCB's, no cases or meters. These were dogs that weren't economically repairable,20 years ago but now they all work fine, half with new Russian transistors, refurbished switches and a variety of transformers. These are kept for trying out new circuit hacks, accessories and upgrades on.

Doing it this way allows more research into the different part numbers (ENi1, ENi2, ENi3) on those transistors, all basically 2N404's, but graded to go in a specific spot. Another historic mystery to unravel!

Geo

In my modest collection there are 3 yellow CDV700 6Bs all ENi's, original not modified.

The oldest one is serial #15 and has the smooth top casting, the newest one is over 19,000 and has the raised lettertopp casting.

Wonder how many ENi's were made in all, there's a list somewhere.

Geo

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digging through parts box, found a new build ENI switch assembly I had bought sometime last year from anythingradioactive out of England.? I don't think they have these anymore, i don't know.? ?

Lithium chemistry doesn't tolerate over charging.?

For example a single cell on a constant current/constant voltage charger could charge a cell at a max current rate of 1C, in the constant current portion of the charge cycle, and? then the current will taper to zero?
as the max charge voltage would be set to 4.20V.
Problem occurs if there are series connected cells. Cell to cell variation, or temperature differences in a pack will cause the cells to age differently so the capacity will vary.
So the cells with lower capacity(mAhr) will charge first and then be over charged unless there is a balance or Battery Management System( BMS) attached to each series connected cell in a pack.?
Basically, the balancer/BMS clamps each cell to a max of 4.20 V

If possible I prefer not have have an integrated BMS( there is some self discharge).? Also integrated BMS's can't tolerate high speed charging as they can't shunt a high current.
I will wire a connector to each cell so an external balancer can be connected, and it also allows me to check each cell voltage in a series connected pack.
Most model RC LiPo packs have a balancer connector.

Paralleling batteries of the same brand/model number is nominally not an issue.

P

Geo:

????????????????????????? Lithium Ion?????????????????? Lithium Iron Phosphate
fully charged????? 4.2V????????????????????????????? 3.6V
discharged????????? 3.3V????????????????????????????? 3V

The voltages I listed for the fully charged is absolute. The discharged voltage can be pushed further down and still be considered safe, but for longer cycle life, i use the above cut offs.
Voltage discharge curve for both types of secondary lithium cells is not flat like NiCd/NimH
C is the capacity of a battery. Lithium batteries have a rated max discharge rate of xxC. Higher C rated batteries will have? a lower mAhr capacity.
Most high C rated batteries are 1800~2500mAhr, while the lower C rate batteries can be more than 3000mAhr.
In addition to the different internal construction and chemistry for the low vs high C rated, the internal PTC ( Positive Temperature Coef) protector is different.
If the current draw is low ie for the CDV-700, the low xxC batteries with the higher mAhr capacities should be fine.
Once again your mileage may vary. Name brand, Sony, Sanyo Panasonic, Samsung, LG chemical are typically good.Others are dubious.
Old stock Lithium cells are a no-no.? The have a limited shelf life and highly depended upon the state of charge when stored.

P

Update, Li cell 18650 on DigiKey, data sheet shows the one they sell as 2600mAh or 2.6A/h Other sources claim far more but one wonders it that's advertising hype.

With even 100mA current, which should be well within the 0.2C rating, a single cell would power an?ENi/LENi/Lionel CDV-700? for at least 26 hours continuous use.

Geo

Many Geiger Mueller probes are available that will work on the CDV-700 but they don't use the standard 900VDC that all 700's provide.

We've developed several circuits to address this issue, both in the single fixed re-regulator, the step adjusted re-regulator, and the continuously adjustable regulator.

Simple but effective single transistor, transformer based HV generators in CDV-700s are robust and purpose built. They are also power hogs. Most are capable of running 1600V safely, as a matter of fact, I cloned them into some pretty useful workbench HV supplies, one at 1600V fixed.

Caveat: within the CDV-700 context, I recommend limiting max. HV? to 1000V. Most Geiger Mueller tubes use far less, with?

400 to 500 being quite common, 700V in US Military RADIACs.

Any of these would work well on any CDV-700, save the wrong HV.

We've also considered completely eliminating the "current hog" HV and LV generator, replacing the with more modern designs.

The following posts will address these different solutions.

Geo

As mentioned in another Bucket List post,?
"Not surprisingly, battery Voltage when using dry cells is not stable over time. I jokingly call dry cells a 1/4 cycle AC generator. Compared to a real sine wave plot, the start at the + peak and go down to the zero crossover level, one time.

This changing Voltage was investigated, and sure enough, even a small change in applied DCV will alter the HV output and LV -15V output, causing changes in meter readings for a steady input pulse signal."

Enter the AMS1117-3.3 regulator module:


Alone this $1 USD module stabilizes the LENi and at least some other CDC-700, It goes in the line between battery or other DC? power source and the battery negative (hot) wire.? It works best from 3.7V up to over 15V. Changing the input V up and down leaves the CPM Meter, HV etc. stable. Perfect for 18650 conversions.

Caveat: Running these AMS1117-xx way above their regulated Voltage ( say, more that a few V) will cause them to dissipate the
excess energy as heat, limiting their current output. For 12V operation it might be wise to first use the similar 5V regulator module ahead of the 3.3V one.

FYI, a converted ENi with SPeak2Me modules is running around 85mA current.

More to follow
Geo

This test has been on the Bucket List for quite a while.

Bottom line, yes they do work, caveat: they don't work quite as well as an actual 2N404A but are easier to find, at least they were when I stocked up on them. Scope traces to follow and those will be good reference for any HV troubleshooting as well.

The difference in performance is negligible but recalibration is necessary, and that probably goes for any transistor swap out, but especially in V1 position - the HV generator. Just a small change in the HV setting will also change the -15V low voltage supply to the metering section, and that Voltage is key to the meter readings obtained. As a matter of fact this test led me to investigate some other stability problems in the ENi/LENi/Lionel CDV-700-6B.



Not surprisingly, battery Voltage when using dry cells is not stable over time. I jokingly call dry cells a 1/4 cycle AC generator. Compared to a real sine wave plot, the start at the + peak and go down to the zero crossover level, one time.

This changing Voltage was investigated, and sure enough, even a small change in applied DCV will alter the HV output and LV -15V output, causing changes in meter readings for a steady input pulse signal.

Geo

PS note the Blue and Yellow theme of the LENisky II PCB. A tribute to Ukraine.

I have what I believe is an Anton board - the transformer sticking off the end.? I might have two of them. Not in cases, just the boards.? Not sure if they work.? Yours if you want them.??

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"In 1991 when the first plane hit"....?
I think you meant to say 2001.? I remember that morning very well.? I worked at IBM and was well paid.? Life was good.? That morning I turned on the news while getting ready for work.? The boss called and said don't bother coming in today.? My stock broker at the time said he lost a friend in one of the towers.??

Cool to see some history/details about your old LeNi hoards...

-Chris

Michael, on the transformer theory, real basic stuff you know already- Voltage in-out is straightforward, it is directly proportional to the number of turns in the "primary" or" power applied winding " to the number of turns in the secondary or "power supplying" winding.?

If being used as an impedance matching transformer, that's a different story, and we can discuss that later of it ever comes up.

CDV-700 turns 3V DC pulses in to ~900V "AC" pulses, but not a sine wave.

The important part concerning the CDV-700 arrangement is the phasing. All transformer windings have a high and low phase relationship compared to the other windings. When stacking windings to get different Voltages, this must be strictly?adhered to.?

If you were using a transformer with one primary and two secondaries on sine wave AC, all the windings, including the primary,? wound in the same direction will have on terminal "High" while the other one is "Low". Just like a car battery is made up of individual cells in series, they must all be pointing in the same directionj to ADD their individual Voltages.
Any one in backwards will "SUBTRACT" it's Voltage. Batteries or cells in parallel must have all their "high" sides hooked together and all their low sides hookked together, otherwise, disaster.

Add a transitor driver to that mix and things get complicated. Transistors in CDV-700 HV and LV supplies are nothing more than switches, working exactly like the "points" in a car ignition. It is nothing more than a switch which turns itself on and off.

So polarity or phase? matter from that standpoint too. If the feedback winding were reversed, when feeding the transistor base the "shutoff" pulse, it would insteaqd turn on even more, not good.

CDV transformers have iron cores, those play an important part on the frequency of when it shut pff during each cycle.

All CDV manuals should have a detailed description of that sequence, and it happens around 100 time each second.



Geo

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no, never got the 4-2 to work.? interesting

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