burnt digitech qm 1535 resistor - Page 1
Forum section: electronics / repair

author: goyo1969
author_rank: Newbie
timestamp: March 08, 2017, 05:34:30 pm
content: Hello there,I've been using the best (!) digital multimeter on the market for the last 10 yers or so without any hassle.By sheer neglect, I managed the blow the ceramic fuse and cook the resistor (r30) at the same time.I searched for a schematic diagram with no success.I would appreciate if someone can tell me the value of that resistor. (colour code will do too)Thanking you,Regards,Goyo

author: RayRay
author_rank: Frequent Contributor
timestamp: March 08, 2017, 06:26:28 pm
content: You might find these handy:http://www.digikey.ca/en/resources/conversion-calculators/conversion-calculator-resistor-color-code-5-bandhttp://www.digikey.ca/en/resources/conversion-calculators/conversion-calculator-resistor-color-code-4-bandGood luck!Edit:Forgot to mention one very important fact, while you could tell the value and tolerance of the resistor from the color coding, it will not tell you the wattage of it! You should check the sizing of it (preferably with a digital caliper) and compare it with datasheets of various resistor wattages in order to make a good educated guess (or simply take it with you to your local electronics store)

author: grifftech
author_rank: Frequent Contributor
timestamp: March 08, 2017, 09:30:44 pm
content: Quote from: RayRay on March 08, 2017, 06:26:28 pmjust get the highest power rating you can shoehorn into the case in theand tolerance you need

author: goyo1969
author_rank: Newbie
timestamp: March 09, 2017, 07:47:37 am
content: Hello there,Thanks for the prompt answers, what I meant with "colour code will do too", I meant the colours on the resistor, so the value can be identified.I was hoping that someone with the same unit can open it up and check the colours on it, take pictures etc..I apologise for the trouble I might be causing.Regards,Goyo

author: smithg27
author_rank: Newbie
timestamp: May 29, 2017, 04:47:06 am
content: Interesting - I just opened up MY 1535 to take a look, and the PCB is quite different from yours.I've attached a photo of my R30 - whichifI am reading the bands correctly (Black-White-White-Silver-Green), wouldappearto be 0.99\$\Omega\$ at 0.5% tolerance, and is a pretty big beast compared with it's neighbour. I can't find any resistor calculators that will allow black for the first band, but that's the value I would interpret given this 5-band colour chart (https://www.digikey.com/-/media/Images/Marketing/Resources/Calculators/resistor-color-chart.jpg).And what a surprise to see that fuse - it is the kind of fuse we had in every domestic 13A plug on every appliance back in the UK, but here in Australia, domestic circuits are only 10A, and plugs on appliances are not fused. Some appliances are fused internally, but they have the smaller glass fuses - I haven't seen one of these since leaving the UK, and here is one inside my MM that I have with me in my toolbox all the time!!

author: Edwin G. Pettis
author_rank: Frequent Contributor
timestamp: May 29, 2017, 05:18:43 pm
content: I believe the burnt band is silver, making this a 4 ohm (yellow-black-black-silver-green), 0.5%, 2 watt resistor. I am surprised that they used such a tight tolerance in a protection circuit, they are usually 2% or 5%. The 0.5% tolerance could make this resistor a bit harder to find.

author: goyo1969
author_rank: Newbie
timestamp: May 29, 2017, 05:49:33 pm
content: Thank you for your replies gentlemen, I purchased the mm fom OZ too, surprise to see the difference. I'll just use my desktop one till I hear from someone with the same unit. Maybe it is the years of difference what makes it unique!Regards,