Tektronix DPO3000 - burnt component on power supply board - Page 1
Forum section: electronics / repair

author: acrove
author_rank: Newbie
timestamp: April 24, 2019, 01:06:07 pm
content: Hi there,I have a Tektronix DPO 3054 oscilloscope with a broken power supply board. The problem is that this board is not longer manufactured. By inspecting the board it seems that only one component is blew up (see pictures) and Tektronix don't give information about what component this is. Do any of you have information about the component?, or any other idea about how to fix the problem??.I have been told by local Tektronix technicians that the power supply board of any DPO 3000 series would be a replacement for my oscilloscope, so if any of you have one I will appreciate you contact me.Thanks a lot,Adrian

author: pbarton
author_rank: Frequent Contributor
timestamp: April 24, 2019, 02:36:28 pm
content: The component looks like a LinkSwitch.Could be either LinkSwitch-TN ICs (LNK302, 304, 305 and 306) LinkSwitch-LP ICs (LNK562, 563 and 564) and the higher power LinkSwitch-XT ICs (LNK362, 363 and 364).

author: acrove
author_rank: Newbie
timestamp: April 24, 2019, 02:53:45 pm
content: Thanks a lot.

author: Testtech
author_rank: Regular Contributor
timestamp: April 24, 2019, 10:55:57 pm
content: I repaired two of these power supply recently. This supply actually has three inverters; one a pre-regulator, one for housekeeping, ie, low current for the front panel, etc, and the main one.The chip that has exploded is an inverter chip, TOP244GN, is there a blown resistor on the bottom of the board?The TOP 244 has a heatsink pad underneath, I used a hot air nozzle to remove.What I did to fix the supply;I removed the heatsink with the inverter transistors and carefully checked them on a curve tracer, one was bad.I replaced that, the TOP244, the opto couplers, burned resistor on the bottom.I also checked ALL the other diodes, resistors, etc.I also replaced all the small electro caps.Take your time, CHECK EVERYTHING, and you should be able to fix it. There are no replacements.

author: acrove
author_rank: Newbie
timestamp: April 24, 2019, 11:10:31 pm
content: Thanks a lot, really, it is very good info.Regards,Adrian

author: acrove
author_rank: Newbie
timestamp: April 25, 2019, 11:22:26 am
content: Hi Testtech,Yes, there is a blown resistor on the bottom of the board (see attachment). Do you know what resistor?Thank you,Adrian.

author: Testtech
author_rank: Regular Contributor
timestamp: April 25, 2019, 02:57:02 pm
content: 10 ohms

author: Jetecnet
author_rank: Contributor
timestamp: August 03, 2019, 07:17:23 pm
content: Hi, Can you confirm 10 ohms, there is an image of this board on Google showing the component as 1R00 (1 ohm),Also the PSU I'm working on has been repaired previously and one mosfet (Q-FET) has been replaced with FQPF9N50C, is this the correct part?The other 2 mosfets are FDP7N60NZ and look original.TIA

author: Testtech
author_rank: Regular Contributor
timestamp: August 07, 2019, 11:47:39 pm
content: I don't have these in the shop any longer. As I recall, I took the value from a working supply when I repaired the bad one.

author: laurentl38
author_rank: Newbie
timestamp: March 30, 2022, 08:21:33 pm
content: Hello,were you able to solve your power supply problem?I too have a similar problem with the resistor blown.can you confirm the value of this resistor?regards

author: mikehank
author_rank: Regular Contributor
timestamp: March 30, 2022, 09:04:13 pm
content: The most common failure point i have found with these supplies are the opto-isolators.