Repairing And Upgrading A HP 16533A Scope Card

In the world of oscilloscopes, as in the rest of the test equipment world, there’s always some trickery afoot. Companies will often offer different models to the market at different price points, in an effort to gain the widest possible customer base while also making the most profit. Cheaper, less capable models are often largely identical to more expensive hardware, save for some software or a couple jumpers that disable functionality. [Alexandre] found just this when working to repair his HP 16533A scope card.

Work began when [Alexandre] received his HP 16533A in the mail after a long wait, only to find the trigger functionality was inoperable. This is crucial on a digital scope, so this simply wouldn’t do. After some research online, a post was found discussing which signals to probe to troubleshoot the issue. It noted that corrosion is a common problem on these units, and that occasionally, a certain resistor goes open circuit and causes problems. Initial measurement showed there was still resistance there, but reading closer, [Alexandre] noted this fateful line:

You might not be able to measure it accurately in circuit. 

Removing the 100K resistor from the board, the part was indeed open circuit. After replacement with a new component, the trigger circuit was again fully operational. With the scope still open, it was then a simple job to execute a further resistor swap which gives the 16533A the functionality and range of the higher-spec 16534A model.

It’s very common for oscilloscopes and other test hardware to be configured this way from the factory. Rigol scopes are particularly popular with hackers for this very reason.

[Thanks to jafinch78 for the tip!]

17 thoughts on “Repairing And Upgrading A HP 16533A Scope Card

  1. Hmm so the co exploited a design issue to effectively cheat the consumer out of $ to performance ratio. Reminds me of the oldie saying about a half penny worth of tar, not immediately relevant but, touches on issue of forethought and it’s consequences betraying intelligence, conscientious and intent…
    Thanks for post cheers :-)

    1. I think you misunderstood the article.

      There were two things that the article touched on:
      1) there was an issue with a failing component
      2) by swapping another component, the customer made the device work at a higher performance standard without paying the extra price associated with it.

      It seems that you are mixing them up or combining these two things that were discussed, and somehow concluding the manufacturer was cheating the customer.
      To me it seems perfectly fair for a company to ask more money for a device that has better functionality, so I fail to see how the company is cheating the customer.

      If you look at it from this angle, the customer essentially cheated the manufacturer.

    2. These scopes were priced outside of individual’s budget. It is mostly purchased or rented by companies that use them for R&D, so low volume high price. One way to cut production cost is to share as much as they can for the base and advanced model.

  2. The way to see it would be that even the base model covered all the development and parts for even the highest specs hence the high spec was just …. price gouging. The base mode is the one and only model costed for the base price. That should be the only price. Its like a car that is capable of higher speeds or longer range except for a jumper setting. At the base price your have paid them for all the parts and the r&d….. you should be entitled to get it as you have paid for it.

    1. Except, we don’t know what goes on “behind the curtain” at manufacturing. The higher performance scopes are no doubt validated to the higher requirements, requiring more validation time and equipment (and thus, money). Do the lower-performance SKUs get that same level of validation? Probably not.

      It could also be like the CPU industry: they build the same device and bin them depending on how they perform during testing. In a scope like the Rigol 1000Z series which has two bandwidths, 50 MHz and 100 MHz, the 50 MHz models may very well be units that fell short of the 100 MHz spec. If you hack a scope to get the extra bandwidth, you don’t really know that you are going to get that full 100 MHz bandwidth back out. Maybe you personally don’t care if the scope falls short to only 95 MHz bandwidth, but someone will very much care about that, and it makes sense for that someone to buy the better model.

      1. This same type of tactic has been seen in high end speakers. Three different prices for the same exact speaker cabinet. The lower end models would incorporate sound dampening materials inside to lower quality. This is a case where it cost them more to make the cheaper unit. You can try to bury the real reason behind these tactics with fancy explanations, but it boils down to ONE basic human disorder. GREED.

        Its amazing how quickly we complicate ourselves beyond understanding…

      2. Yeah, ok, I see your point. It’s a quality control thing. Instead of ditching the units that don’t pass a certain performance perhaps because of just component tolerances all conspired in a bad way, they define a cheaper model and disable the higher bandwidth.

    2. Another possibility is that the margin is lower than is sustainable on the cheaper model but they’d rather make the sale on the cheaper model than not at all, which would increase the price of the more expensive model too (fewer sold, less return on a given design). My DS1054Z came pre-hacked but I would have been happy with 50 MHz and am delighted to have a sensible scope within my budget.

      1. Yep I see but we will never know and that is what irks me to a degree. I guess it is a boardroom/management discussion but somehow I would like to honestly know. Ok either we up the price as there are way too may built units failing to meet the high specs or we downspec those sell them cheaper and help offset the losses from the high
        end units. It is all possible. Even the case that they just make a call that making one board is cheaper than two separate production runs and then they disable opions and make that the entry unit and the full monty gets a much higher price tag and full specs but even the entry unit pays for all the components as that would be a bad call to make any unit at a loss unless purely as a promotional excercise for a limited timeframe. I am finding it more and more difficult to trust corporations and their boards because of their profit motives. The older I get and the more I see of their behaviour the more cases are exposed of nefarious goings on. I see price as just one measurement point not the be all. Doing the right thing is multifaceted thing, even the most profitable company can only be or remain so if the value is excellent from the customer end of things. Having said this, it will also be short lived if they don’t treat their staff right. And it will definitely tank sooner or later if they trash the environment or fail to pay their suppliers right or taxes etc etc but I have digressed sorry.

        1. I don’t get it. Why the anger about the different prices for the “same” hardware?

          Let’s go back to the Rigol example. The manufacturer makes two units with identical hardware. One is “programmed” to work at 50 MHz. The other at 100 MHz. Do you really think you should be able to pay the same for both versions? Or that there should just be one version, because they “shouldn’t be different”?

          It’s irrelevant what the hardware cost the manufacturer – the second version allows you to measure twice the bandwidth.

          Maybe someone will think “oh but the first one should have been as good as the second one, or the second one as cheap as the first one, but we were cheated out of it”. No. For extra functionality, you pay extra, seems very reasonable.

          Perhaps they tried to make only 100 MHz versions, one didn’t quite make it, and got sold as a 50 MHz one. Better for the environment to still sell them, right? If you just chucked them away, it would make everything more expensive.

          The first purpose of a company is to make a profit. Without a profit, they cannot remain a company. Even if they made less than 10 % profit, they probably would not last.

          You’re not forced to buy a scope. If you don’t like it, don’t buy it. If enough people don’t buy it, the scopes will be reduced in priced or removed from the market.

          There is nothing dishonest about this.

          If I somehow made it possible to turn a 100 MHz Rigol scope into a 200 MHz Rigol scope with the same hardware and perfect performance, wouldn’t that be worth more to you still?

      2. I don’t know about manufacturing of scopes, but I can tell you that in my industry (chip fabrication) we look at pricing by saying: this chip will be viable on the market for only a certain length of time, and then we have to forecast purchases over that period of time at different prices to maximize the income. One of the things that goes into that forecast is process improvement over time: we know that the first few lots will have a lower yield, and there will be more parts in the barely-passed bin than in the did-great bin. We also have to price based on the knowledge that over time, our production cost will fall, but the market will demand our per-unit price also fall, and we need to make sure that the initial prices of the different bins (standard or wide-temperature-range, for instance) are high enough that we will still be making an acceptable overall profit right until the end of life.

    3. I’m thinking market share capabilities when researching sales. From my experience in drugs and medical device sales… marketing/sales will sell something that doesn’t exist yet.

      Next thing you know there may be a product in a certain dosage form or dose that is already in development or developed and their isn’t some sort of exclusivity… so you modify what you have formulated/designed with approved materials and produce that formula design valid that can be sold to the approved vendors/clients that made the orders sooner than later so orders aren’t canceled.

      Now, with electronic devices I’m thinking there is something somewhat similar going on. Marketing might be like… hey… we can make this many sales to this market base/demographic and this many to this and blah blah blah clients need this and that… ultimately with more options for sales and consumers able to invest in the manufactured device with lower cost on investment.

      Then engineers might be like… bro/sir… we can do a couple designs on the same board since they sold the design already and it’s hot and they want X number of units by some date. Maybe design from the start the versatile PCB or in a revision to an existing.

      So… use one PCB (board) for a couple designs (or some call cards/blades where at least the interface connection is the same) and next thing you know you populate some pads and traces for some designs systems components and you don’t for the others or you populate with different components for the different designs.

      Due to Non Disclosure Agreement (NDA’s) and the concept of not owning property, unless you’re not a slave in the upper middle class on down…, we as a consumer can reverse engineer to see what can be done.

      This in a similar business model of do what “we the business” can get away with, though probably more lawfully as consumers since we own the property really versus public funds, investors, stakeholder, as well as hope some in the rumor mill give us the daily grind and word of mouth through the grape vine on down to release some info where those on the doesn’t look like and sound like the big high rollers pay scales can improve their devices or at least maintain them since now the borders of nations aren’t so much an issue as the boundaries of socio-economic class investment capabilities.

  3. Hi there, thanks for the comments to my article :)
    Let me expand the subject, there is a post before this one shown here, with the solution to the FIRST problem

    I got this board in a non-working state. Some tests failed, and I noticed the corrosion on the isolation rails below the card. If you take a look on the earlier post, you’ll all see the corrosion caused by humidity on the double-face tape of the plastic rails and the solution. This is a very important subject (if you havn’t this problem until now, you probably will have it) and I wanted people to take a look at his/hers cards and remove the plastic rails and the glue, it can e done with some IPA.

    The earlier post with a video in english:
    This is a VERY delicate situation, I urge you who has an HP logic analyser to take a look at your cards. You can loose a lot of money if you don’t care. Greetings from Brazil!

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