Bought a 20Mhz Hameg Oscilloscope - can I "upgrade" it to 100Mhz? - Page 1
Forum section: electronics / beginners

author: sgtberbatov
author_rank: Newbie
timestamp: March 23, 2017, 04:52:06 pm
content: Hi everyone,First time poster, long time stalker on the YouTube channel! I have had an interest in electronics since I was at school, however the last bit of work I've done in electronics was for my GCSE in 2004. Now, in 2017, I have some money and a need for a new hobby, so I have decided to get back in to it!I'm in the process of building up my equipment, and recently I purchased a Hameg oscilloscope from eBay for about £50. It's 20Mhz, which is enough to get me going at least. On an Amiga group on Facebook, someone mentioned that I should "upgrade" it to 100Mhz. I didn't think this was possible? For the small projects I have lined up I think 20Mhz will be sufficient, but the idea of upgrading this to do more is appealing.So I'm just wondering whether it's at all possible or feasible to upgrade my oscilloscope to 100Mhz? Or is it something I don't need to do or something I would be better off just buying a 100Mhz one from eBay?

author: grumpydoc
author_rank: Super Contributor
timestamp: March 23, 2017, 06:25:48 pm
content: If you mean a 20MHz Hameg analogue 'scope with a CRT then, no, I'm afraid there is nothing you can do to turn it into a 100Mhz oscilloscope - except sell it and buy a 100Mhz oscilloscope.In the advice that you were given the word "upgrade" should be read as "replace".That said there is nothingwrongwith a 20MHz 'scope if it is doing the job that you need it to do. Don't rush to change until you build up experience to know what features you need.

author: james_s
author_rank: Super Contributor
timestamp: March 23, 2017, 06:57:10 pm
content: You have to post the model number in order for anyone to help.The only scopes you can hack to gain higher bandwidth are modern DSOs where it is cheaper to build a bunch of different models that are all identical hardware and then enable certain features based on the price tier. On some of these you can trick them into thinking they are one of the higher end models since the hardware itself is the same.

author: sgtberbatov
author_rank: Newbie
timestamp: March 24, 2017, 09:29:04 am
content: My apologies about the lack of a model number. I was at work when I posted it and I got home to find my house destroyed by a dog with the squits. Wasn't fun!Yeah, it's the Hameg Analogue scope with the CRT I have. I bought it because it was 20Mhz on the advice Dave gave in a previous video. When the 100Mhz upgrade was mentioned I thought it'd be a handy way of making more of the equipment without buying more stuff. But I fully understand where the upgrade bit comes in to it and how/what that applies to.At the moment I have a project where I want to digitise the dashboard of my 1998 Corolla, so I'm 99% sure this oscilloscope is more than adequate. Thanks for the advice guys!

author: Arjan Emm
author_rank: Regular Contributor
timestamp: March 24, 2017, 09:39:41 am
content: Again model number? Hameg made many different 20Mhz scoops with a crt.

author: Rerouter
author_rank: Super Contributor
timestamp: March 24, 2017, 09:59:13 am
content: also something to be aware of, 20Mhz isn't a brick wall that you cannot see any signals greater than at, its just the 3db point of the input circuitry's filter, my Tek 475A scope can still see 1Ghz signals, they are just pretty rounded by that point, and i would not be able to trust the amplitudesIf you just want to see whats going on at those higher frequencies, you can still extract something out of it, 1Ghz would be a stretch for you, but you may be able to atleast see that a 100Mhz signal is toggling,An analog scope and a ebay logic analyser should be all someone needs to diagnose most systems on the cheap as dirt level budget, again, may not be the easiest, but it will get the job done,

author: alm
author_rank: Super Contributor
timestamp: March 24, 2017, 12:51:12 pm
content: While the bandwidth limit is not a brick wall, triggering bandwidth and sensitivity are also limited. So you may not be able to trigger at all, or only be able to trigger of the signal is at least X divs high.If you need a 100 MHz scope, buy a 100 MHz scope. But for plenty of beginner applications 20 MHz should be sufficient.

author: EEVblog
author_rank: Unknown
timestamp: March 24, 2017, 12:56:58 pm
content: Quote from: sgtberbatov on March 24, 2017, 09:29:04 amI have never seen an analog scope with a deliberately crippled front end bandwidth.Who ever told you that is almost certainly wrong.

author: alm
author_rank: Super Contributor
timestamp: March 24, 2017, 01:10:29 pm
content: I believe the Tek 2445 series (~150 MHz bandwidth) could be kind of upgraded to the 2465 series (~300-400 MHz bandwidth) by bypassing an inductor. Not an exact match, and I am sure it did not meet all 2465 specs, but it did certainly increase their bandwidth substantially. Would obviously require a new calibration. This would only apply if there were higher bandwidth models in the same series and the manufacturer used the same (or very similar) CRT and circuits for both models.

author: grumpydoc
author_rank: Super Contributor
timestamp: March 24, 2017, 01:37:29 pm
content: Quote from: EEVblog on March 24, 2017, 12:56:58 pmThe Phillips/Fluke combiscopes have the same front end in the 100MHz and 200Mhz 'scopes with different component values tweaking the bandwidth so, in theory, you could upgrade a board from 100MHz to 200MHz - it's quite a lot of components though and the delay line and CRT are different in the 200MHz 'scopes so it's not really possible to upgrade a 100MHz 'scope into a 200MHz 'scope.The digital boards in these 'scopes have a much smaller number of different components differentiating the 100MHz and 200MHz versions although I failed when I tried to upgrade a board - I think that this is because the change might muck up the biasing in the custom analogue amp/multiplexor that the boards use. It doesn't matter though because even in the 100MHz version there is enough adjustment to calibrate it for 200MHz operation with very little performance loss.Quote from: alm on March 24, 2017, 01:10:29 pmMy understanding is that the 2445 and 2465 areidenticalexcept for a jumper and some compensation components in the delay line driver. However as those differences include inductors fabricated with buried PCB traces it is, again, not possible in practice to turn one 'scope into the other and you'd need to be able to do a full re-cal to check the frequency & transient response.A few years back there was an ebay vendor who was vilified on the TekScopes list for bypassing the inductors and selling de-badged 2445's as 2465's.Edit: the Hitachi V665/V1065 are also the same 'scope with a few components changed to alter the bandwidth.Not sure if you count that as "crippling" the front end or not.

author: oldway
author_rank: Super Contributor
timestamp: March 24, 2017, 02:42:51 pm
content: The technology of a crt of 20Mhz and that of a crt of 100 Mhz are totally different so the first thing you should do is change the cathode ray tube.The 100Mhz cathode ray tubes use a post acceleration of 10 or more KV's and those of 20Mhz not.It would therefore also be necessary to add a 10KV's power supply and to completely modify the vertical inputs amplifiers (insufficient bandwidth) and the time baseIn short, such a modification would be a ugly lame duck very expensive and full of problems....So, answering to your question: no, you can't !Nb: crt's of Tektronix 2445 and 2465 are the same.

author: james_s
author_rank: Super Contributor
timestamp: March 24, 2017, 09:07:09 pm
content: The person who gave this advice was probably thinking of some of the Chinese digital oscilloscopes that can be hacked and mistakenly believed that it applied to other scopes as well. Analog oscilloscopes are designed around the required bandwidth, virtually every part of the circuit needs to be done differently to achieve higher bandwidth. They are very unlike a modern DSO where just the front end and capture hardware needs to deal directly with the signal and it's cheaper to build one design and cripple it for lower cost models than to create multiple separate designs.