Inexpensive Huntron 2000 Design (Possibly using DSO138 Kit)? - Page 1
Forum section: electronics / projects

author: Chris56000
author_rank: Frequent Contributor
timestamp: March 02, 2019, 06:36:30 am
content: Hi!The prices being asked for old Huntron 2000 Component Trackers, even "parts only" ones, have now gone up into the bloody stratosphere, which, given the manual with schematic is freely available online, led me to further thoughts:–1) Whilst I've not yet tried seeing if I can extract the 87C52 dump from my employer's unit, whose CRT is approaching the end of it's useful life, would it be too difficult to program a Nano or PIC to read the button functions of a Huntron 2000 and provide switch/pwm outputs for the H2000's analogue circuitry, if Huntron have set the 87C52's lock bit?2) Is the DSO138 JYE Oscilloscope Kit with TFT fast enough in response to be used as a display in lieu of a CRT (saving the need for a CRT with the associated high–tension voltage supplies it would need!), and if so, will it run in x/y mode?3) If this is feasible, can a larger size TFT module be fitted to the DSO 138 kit or does this require code alterations?If members can look at my idea and point me in the direction of code libraries/Arduino tutorials I'd be very grateful! Is there a "GitHub" repo for the DSO138?Chris Williams

author: Gyro
author_rank: Super Contributor
timestamp: March 02, 2019, 10:21:54 am
content: QuoteI remember seeing a thread on bigger displays in the JYE DSO138 forum...https://jyetech.com/forum/viewforum.php?f=18&sid=f7b11da47f69d3b4c26a35306f5d1741

author: Chris56000
author_rank: Frequent Contributor
timestamp: March 02, 2019, 04:24:28 pm
content: Hi!A quick update on this thread and another question - I've just been looking at the Huntron 2000 Maintenance Manual and there's no Micro Dump to worry about - the instrument is entirely discrete CMOS logic operated with no micro in it - I must have been looking at the manual for a different model!However, on the circuit diagram (Page 90, Huntron Front Panel Schematic, Huntron Page Ref 6.3):-https://s3.amazonaws.com/Icarus/DOCUMENTS/HUNTRON_Manuals_1771.pdf. . .can anyone tell me what an "RZ Taper" is, as referred to next to R8, "RATE ADJ." control please, and would I be able to get one?Chris Williams

author: tsman
author_rank: Frequent Contributor
timestamp: March 02, 2019, 04:43:24 pm
content: Quote from: Chris56000 on March 02, 2019, 04:24:28 pmReverse log taper on the potentiometer.Might be hard to find a 1M reverse log pot though...https://www.digikey.com/products/en/potentiometers-variable-resistors/rotary-potentiometers-rheostats/84?k=&pkeyword=&sv=0&pv1=37&sf=1&FV=ffe00054%2C11100004&quantity=&ColumnSort=0&page=1&pageSize=25

author: Chris56000
author_rank: Frequent Contributor
timestamp: March 06, 2019, 10:33:18 am
content: Hi!I've now found several Reverse log 1M pots from ebay and other sources, can anyone suggest wether the transformer kit here:-https://www.ebay.co.uk/itm/171950796418. . .would be suitable for making the signal voltage transformer shown in the circuit-extract attached? The primary would be driven about 24-28V pk-pkfrom a modern replacement (cheap eBay P.A. D.I.Y. kit) to the LM759 used here, and the secondary would be 10, 20, 40 & 60V RMS at frequencies of 50, 400 & 2000Hz. The maximum power into the primary I estimate at 8W under s/c conditions, much less with normal good components.The transformer needs to provide about 150mA RMS current o/p on the lowest voltage tap, 25mA on the others., what wire-gauge would be suggested and where can I find design resources for such a transformer?Chris WilliamsPS! My training & experience is in repair, this is the first time I've ventured into winding small transformers for new projects!

author: SpencerTC
author_rank: Contributor
timestamp: March 06, 2019, 02:20:40 pm
content: I have wanted a Huntron tracer/tracker for some time.In order for me to be able to afford quality instruments for my home lab I often must purchase them in a broken state and repair them....I have as many broken "projects" as I do working gear right now *blush* and after learning what exactly a Huntron was, I instantly wanted one, and as you mentioned, they are quite expensive, even on the used market....and even broken.I considered the idea of converting one of my old analog scopes into a clone of the Huntron concept, but haven't made much progress on that idea, but I will briefly explain my idea.I was going to do the following: Buy, build, and install one of those curve tracer kits onto an old oscilloscope. Build a simple function generator and have it in the same enclosure. Build a circuit to control the switching (and possibly positioning offsets) between 2 sets of test leads that would either let me manually switch between signal A and signal B, quickly alternate between signal A and signal B, or divide (and/or subtract) A from B to show deviation from an ideal straight line.I am terrible at documenting projects, but if I end up designing/building this project soon I will try to document it and post it here.Good luck!

author: Chris56000
author_rank: Frequent Contributor
timestamp: March 06, 2019, 07:17:00 pm
content: Hi!Documenting equipment & components is something I KNOW I can do a good job of that any Member on here will be able to follow, but as I said I was trained in repair rather than design!The transformer I propose to make will be an approximate equivalent to Huntron's original with a primary energised at 9.5V r.m.s. using sinusoidal i.c., fed from a three–frequency (50 Hz, 400 Hz & 2000 Hz) oscillator board, fed into a power amp using a cheap eBay P.A. module.The secondary will be either a single multi–tap winding of 10, 20, 40 and 60V, or two windings of 10V and two windings of 20V, depending on which I find easier to make!The current needed is 150mA for the two 10V secondaries and 50mA for the two 20V secomdaries.Once I've tested the transformer I'll publish full core and winding details!A pre–programmed micro is NOT needed to build this instrument but if any Software skilled Member has any input for programming a PIC or Arduino Nano, etc., it would be a nice extra!Chris Williams

author: floobydust
author_rank: Super Contributor
timestamp: March 06, 2019, 07:29:28 pm
content: The signal output transformer 06-6034 is a custom audio transformer by Huntron. It's pretty big, several VA.Four secondary taps:HIGH 60Vp Isc=0.57mA RMS {pdf pg.54}MEDIUM 2 20Vp Isc=0.53mA RMSMEDIUM 1 15Vp Isc=8.5mA RMSLOW 10Vp Isc=132mA RMSI'm guessing the turns ratios are 1:1, 1:1.5, 1:2 and 1:6The internal signal generator is a couple XR2209 for 80,400,2kHz and xfmer driven by two parallel uA759 power op-amps +/-200mA off +/-12V, roughly 10Vp drive.If you add feedback including the transformer secondary or simply make the drive (R35) switched values, you could simplifiy the circuit.I would consider TDA2003 or a discrete transistor amplifier to drive it.