Have a look here for relays.
https://www.surplussales.com/Relays/REReed-1.html
All sorts of obsolete junk here. Might even find the original.
https://www.surplussales.com/Relays/REReed-1.html
All sorts of obsolete junk here. Might even find the original.
No originals, I looked. However several possibilities. iut also shows the numerois phisical configurations used over the years. The odd think here is the spdt function on a reed relay. They are normally NO contacts. NC contact reeds are very uncommon.
One on the list would work, however the pins would need a lot of bending-(KO) 194HE3C21943
One on the list would work, however the pins would need a lot of bending-(KO) 194HE3C21943
Depends on what you are looking at. For amplitude accuracy in source and measurement the Boonton is much better. For frequency accuracy and attenuator accuracy as well. On a carefully adjusted stock 1120 the distortion residual can be as low as -106 dB. The oscillator is more like -100 dB best case. It also has filter options and measures SINAD etc. And can be computer controlled.
For $300 to $400 they are good. I think the $1k prices on eBay are nuts. I would get an AP system 1 at that price.
I have a long list of mods I'm working through for it that gets the residuals down some.
For $300 to $400 they are good. I think the $1k prices on eBay are nuts. I would get an AP system 1 at that price.
I have a long list of mods I'm working through for it that gets the residuals down some.
Have a question about the Boonton 1120/S1. Is there a manual for it? I have the 1120 and 1121 manuals. The power supply seems to be identical to the 1121 and there is a amplifier board in the power supply area too, which also looks to be like the 1121. If there is a manual, I would like to get a copy or point me in the right direction to find one. Let me know!
I am having the same errors come up on both of my Boonton 1120s and wanted to know if anyone can steer me in the correct direction for a fix. I get Error 66 and 67 when I run test "33" on both units. I also get Error 43 when I run test "24". What could be causing these errors? Both units have new capacitors and one unit has LME49710/20 subs for the NE chips.
Do you have copies of the manuals? PM me if you need them. Those errors indicate issues in the input PCB and the filter PCB. Make sure you have the opamps in correctly and the right kind (I have too many times stuck a dual in a single socket). The manual says where to look. mStart out measuring voltage from 1V to maybe 6V and see what you get. That should be easy to fix.
The hardest one I ran into was a failed optocoupler on the main board. I just replaced all of them since finding it would take forever.
The hardest one I ran into was a failed optocoupler on the main board. I just replaced all of them since finding it would take forever.
If you are in the SF Bay area, you may be able to get a 1120 for little, along with a lot of other stuff. Listed as broken, needs repair, as is all the pallet.
LOT OF OSCILLOSCOPES AND ELECTRONICS FOR PARTS OR REPAIR | eBay
If I was closer I'd probably buy it, but don't fashion a drive down to pick it up.
cheers
Alan
LOT OF OSCILLOSCOPES AND ELECTRONICS FOR PARTS OR REPAIR | eBay
If I was closer I'd probably buy it, but don't fashion a drive down to pick it up.
cheers
Alan
Boonton has updated and revised the 1121 to the 1121A. The complete and detailed manual is here: Boonton - 1121A Audio Analyzer Some boards have been redone but with the same circuits, just surface mount. other had some changes (the notch filter for example) because some parts don't exist any more. Its still pretty relevant to older units.
I’ve recently bought a Boonton 1120 and thanks to the excellent work done by Demian and Mike I’ve followed some of the mods you’ve suggested. My notch board is an earlier version I think, 112017, and the resistor values around the tune and balance circuit are slightly different (R42/43 1k, R47/50 47k7, R48/49 100k), so I haven’t done that part yet. Replacing the 5532/4s with 49710/20s has improved lowest distortion measurement from 0.0015% to 0.0008% using Viktors’ oscillator and with the new R42/3 values, the null adjustment is much easier. Does anyone have a schematic for this version?
Using the layout suggested my Demian, I’ve done an Eagle layout and built a 440Hz and audio board, and these are working well (see photo).
I have one problem though: whatever filter I put in the left hand position on the board, the level and distortion measurement read low (level 2v instead of 3v). Both boards work fine in the right hand position. I’ve entered the special codes from the manual to show which board is in which position, but I’m wondering of the codes are different on my model, or I’m doing something wrong. Any Suggestions?
I have some spare boards if anyone in the UK wants one, and can post the Gerbers/Eagle files if anyone is interested.
Thanks again for helping to improve this great piece of kit, it’s good to work on something where the manual gives such a wealth of information.
Andy
Using the layout suggested my Demian, I’ve done an Eagle layout and built a 440Hz and audio board, and these are working well (see photo).
I have one problem though: whatever filter I put in the left hand position on the board, the level and distortion measurement read low (level 2v instead of 3v). Both boards work fine in the right hand position. I’ve entered the special codes from the manual to show which board is in which position, but I’m wondering of the codes are different on my model, or I’m doing something wrong. Any Suggestions?
I have some spare boards if anyone in the UK wants one, and can post the Gerbers/Eagle files if anyone is interested.
Thanks again for helping to improve this great piece of kit, it’s good to work on something where the manual gives such a wealth of information.
Andy
