[volt-nuts] DAS-46, 47 and other models using the CSA

For those with an interest in the subject devices, another member, Orin, and I have developed a schematic and model of the Chopper Stabilized Amplifier (CSA) that seems to model the actual to a high degree of accuracy. I will post it up someplace if given a target location. My particular

Re: [volt-nuts] DAS-46

I just sent Charles a note off-list. This morning I received replacement FETs for the MFE3002 using ECG220s. These came with a little spring around the leads keeping the leads shorted as they are high impedance. I replaced the suspect FET and the unit is working! Go figure, as I suspected I

Re: [volt-nuts] DAS-46 CSA cost

Actually, not too bad considering they probably have to dig out the components and build/test one by hand. If it weren't so much, it would be interesting to see whether they have redesigned it to use more modern components. On Mon, Jan 30, 2017 at 11:02 AM, Jerry Hancock

[volt-nuts] DAS-46 CSA cost

I received a note from Prime Technology today and the CSA will cost $425 with a lead time of 10 weeks. Ha! I can purchase 3 or 4 of them for that price. Anyway, I don’t blame them. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to

Re: [volt-nuts] DAS-46

Jerry wrote: One of the items I am having trouble modeling is a CLD, current limiting diode, MCL1302. CLDs are almost always operated in saturation, so a behavioral current source of the appropriate value should model it just fine for your needs (spec for the MCL1302 is 2mA +/- 0.6mA -- as

Re: [volt-nuts] DAS-46

Well, you aren’t going to believe this, but I’ve checked the circuit about 10 times now and it looks pretty good. I then used Charles advice and imported the CCL2000 CLD. I ran the model and it swung to the negative rail to almost the exact voltage I am getting with the real circuit of

Re: [volt-nuts] DAS-46

Charles, thank you! Very helpful, as everyone has been. > On Jan 29, 2017, at 6:38 PM, Charles Steinmetz wrote: > > Jerry wrote: > >> One of the items I am having trouble modeling is a CLD, current limiting >> diode, MCL1302. > > CLDs are almost always operated in

Re: [volt-nuts] DAS-46

Yes, and I assume you would need an FET that acted like the CLD. I believe the MCL1302 is a 2mA device. I doubt I’[ll get the model working, which would be ideal. > On Jan 29, 2017, at 3:20 PM, Bruce Griffiths > wrote: > > A CLD is merely a JFET with the gate

Re: [volt-nuts] DAS-46

A CLD is merely a JFET with the gate connected to the source.Sometimes a source resistor may be included with the gate connected to the opposite end of the resistor to the end connected to the source. Bruce On Monday, 30 January 2017 12:12 PM, Jerry Hancock wrote:

[volt-nuts] DAS-46

One of the items I am having trouble modeling is a CLD, current limiting diode, MCL1302. The CLDs are used between he base and collectors on the output stage 2n2219 / 2n2905. I swapped them on the board with no impact on the problem. I can’t find CLDs in LTSPICE. The other diode I can’t

Re: [volt-nuts] DAS-46

Jerry wrote: I traced the issue to a Chopper Stabilized Amp on the back of the power supply board. Unfortunately, the CSA has no schematic supplied. If it fails, it is to be replaced. I’ve been trying to reverse engineer it into LTSpice without luck. There are two FETs, MFE3002 that cross

[volt-nuts] DAS-46

Hello, fellow volt-nuts. Several weeks ago I was able to pickup a Fluke 332D and a DAS-46, both in nice shape. Dr. Frank helped me with the 332D which required the replacement of a resistor (two in parallel) in the string to get the 332D working. The DAS 46 worked perfectly for a week and