Hi, perfect, another beautiful piece rescued, always liked these oscillators, but my work surface is not big enough to afford one, so I restored the HP209A. Nice day 🙂Tom
One thing, the Tek AA501 Monitor output is not just buffered, it is normalized to 1VRMS above 50mV input. So you can't just treat the AA501 as an attenuator. The idea is that you never have to tweak the scope that is monitoring the monitor output, just set it to 1V/div or whatever suits you. Below 50mV input it applies gain of 20.
I will head back in an check that one for leakage but that position was in the oscillator section if I remember correctly I expected Mylar construction rather than paper. It also had a different physical style to the paper caps. Mylar would be fine to leave behind and will serve for years to come. Paper would need a replacement. A paper type cap will not hold frequency due to drifting properties even when they were new.
@@ZenwizardStudios I want to use it for audio testing speakers. Do I use the jumper or not ? Thanks for the reply, I appreciate it. Not much I can find on hook up.
For me for normal use the jumper is fine. It needs to be removed when the DUT need differential signaling at its input a higher end audio amplifier as an example that takes advantage of the - going signal.
I could do a video on that topic if it would help that one might be better explained long form. The shortish explanation is differential signaling is a noise reduction technique that is some times used in audio circuits but is EXTENSIVELY used in high speed digital circuits. Pretty much EVERY Ethernet and USB device uses differential signaling to get the data down the wire. The best way to look at it is the signal has a Data + and Data - line the data - line is exactly the same data as the + side just inverted. This is what creates the “eye diagrams” used in grading the signal quality
@@ZenwizardStudios Date on the bottom of the choke says 1971 FWIW... of course they may have had a decade's worth of parts. Supposedly they made these into the 80s.
Replace the Sprague mul-sections could be not a good idea, I went through dozens of HP Never found a bad caps, just re-form them, newer caps guaranteed not better!
I like your channel because you deliver the knowledge without the burden of any personality or palpable passion. Keep up the good work.
Hi, perfect, another beautiful piece rescued, always liked these oscillators, but my work surface is not big enough to afford one, so I restored the HP209A.
Nice day 🙂Tom
One thing, the Tek AA501 Monitor output is not just buffered, it is normalized to 1VRMS above 50mV input. So you can't just treat the AA501 as an attenuator. The idea is that you never have to tweak the scope that is monitoring the monitor output, just set it to 1V/div or whatever suits you. Below 50mV input it applies gain of 20.
Great video! Is that black beauty still holding up? 32:40
I will head back in an check that one for leakage but that position was in the oscillator section if I remember correctly I expected Mylar construction rather than paper. It also had a different physical style to the paper caps. Mylar would be fine to leave behind and will serve for years to come. Paper would need a replacement. A paper type cap will not hold frequency due to drifting properties even when they were new.
I have one of these that's in decent shape... but hasn't worked since the 90s... I would love to restore mine... Do you accept repairs?
Why is there a jumper on the front From positive to negative ?
It can be used double ended or signal ended because of the output transformer This is currently set up for signal ended mode.
@@ZenwizardStudios I want to use it for audio testing speakers.
Do I use the jumper or not ?
Thanks for the reply, I appreciate it.
Not much I can find on hook up.
For me for normal use the jumper is fine. It needs to be removed when the DUT need differential signaling at its input a higher end audio amplifier as an example that takes advantage of the - going signal.
@@ZenwizardStudios I'll try my best to interpret the nomenclature.
Thanks again.
I could do a video on that topic if it would help that one might be better explained long form. The shortish explanation is differential signaling is a noise reduction technique that is some times used in audio circuits but is EXTENSIVELY used in high speed digital circuits. Pretty much EVERY Ethernet and USB device uses differential signaling to get the data down the wire. The best way to look at it is the signal has a Data + and Data - line the data - line is exactly the same data as the + side just inverted. This is what creates the “eye diagrams” used in grading the signal quality
The later 200CDs were factory with the newer style power input
I do like the newer style IEC connectors, they make life a lot easier. Good to know this is a later unit.
@@ZenwizardStudios Date on the bottom of the choke says 1971 FWIW... of course they may have had a decade's worth of parts. Supposedly they made these into the 80s.
Look at the label, HP had a CD back i a days, hi
Replace the Sprague mul-sections could be not a good idea, I went through dozens of HP
Never found a bad caps, just re-form them, newer caps guaranteed not better!