Monitoring, Day Sequerra Board Repair

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Bill DeFelice
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Monitoring, Day Sequerra Board Repair

Post by Bill DeFelice » Wed May 16, 2018 9:39 am

I thought some of you might be interested in my repair and rework of a DaySequerra M2 with a bad bargraph display board where I demonstrate how I work on SMT mounted components:

DaySequerra M2 Mod Monitor: Bargraph Display Board Repair

There's a series of photographs that chart the journey along the way back to operational condition.
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Re: Monitoring, Day Sequerra Board Repair

Post by kcbooboo » Thu May 17, 2018 5:16 am

I owned one of those units for a couple of months. The blue LEDs were bright enough to light up my entire house! Unfortunately even after a trip to the factory to be updated and calibrated, the unit still didn't perform up to my requirements and I refused to send it to them for another month. The quality of construction was far below par. I was happy to get rid of it.

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Re: Monitoring, Day Sequerra Board Repair

Post by Bill DeFelice » Thu May 17, 2018 6:08 am

I had a similar experience with mine. It came back and the high level RF inputs no longer worked. Performance was tepid at best and the bargraph LEDs burned out, related to they receiving a batch of bad driver chips which would send spikes and burn the LEDs out.

I'd buy an Inovonics or Belar HD monitor if I had the bucks but for the amount of consultancy I do I can't justify it. My trusty Belar and Inovonics analog AM and FM monitors have never given me a lick of problems and they're significantly older than the M2.

BTW: I think you got off easy. If I remember, it took mine three months before I saw it again.
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Re: Monitoring, Day Sequerra Board Repair

Post by NECRAT » Thu May 17, 2018 10:22 am

WPRO in Providence took theirs and modified the bar-graphs to be a dimmer, easier on the eyes green color. I remember their engineer telling me how they modified the unit because the blue was too harsh.
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Re: Monitoring, Day Sequerra Board Repair

Post by kcbooboo » Fri May 18, 2018 4:40 am

I suppose the M2 is better than nothing, but its accuracy was far from what you'd need to assure FCC compliance. I wonder what the FCC uses, by the way, when they investigate overmodulation complaints? There was one pirate station in my town a few years ago that was running 40 kHz deviation on their 19 kHz pilot tone, so you can imagine how loud the actual audio was.

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Re: Monitoring, Day Sequerra Board Repair

Post by Deep Thought » Fri May 18, 2018 8:04 am

kcbooboo wrote:
Fri May 18, 2018 4:40 am
I wonder what the FCC uses, by the way, when they investigate overmodulation complaints?
Overmodulation complaints? I don't think I have seen a station cited for overmodulation in the last 30 years.

They do have nifty equipment...a modified spectrum analyzer/SDR which is also used for interference and pirate tracking so it's not like they can't do anything about it. Their main enforcement philosophy is "if it stays in the band an nobody complains, we'll move on to something else". I know of one instance where a station was coughing out spurs for years until a ham radio operator complained about it...and suddenly the EB was all over the place.
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Re: Monitoring, Day Sequerra Board Repair

Post by Bill DeFelice » Fri May 18, 2018 2:57 pm

Mind you, this comes from someone who's never really dealt with the HD side of things, but I'm curious just what is considered 100% modulation for the digital audio stream. I've been discussing with colleagues about the different references in luFS (loudness units full scale). Since I've never studied the aspects of HD in detail I'm wondering what is actually considered 100% modulation in the digital sense. With that in mind I wonder if that's what the M2 is suppose to read as I would expect it's not some arbitrary value.
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Re: Monitoring, Day Sequerra Board Repair

Post by Deep Thought » Fri May 18, 2018 6:18 pm

100% in the digital IBOC realm is all ones. If you try to go over that really *really* bad things happen in the codec. I suspect that anything you see over 100% on the "HD" audio display is overshoots in the decoding. I'll have to scan around the Chicago FM band with my M2 and see if I can find any real differences between subchannel streams.
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