Metcal stss-002 / RFG-30 soldering station repair - Page 1
Forum section: electronics / repair

author: kirill_maker
author_rank: Contributor
timestamp: November 25, 2024, 12:53:06 pm
content: Hi! I got myself an alien-tech soldering station based on RF heating (approx. 13.5 MHz) by Metcal (type STSS-002 / model RFG-30) with a bunch of tips (23 in total).The problem is that it stays red without heating, which isn’t normal.Here’s what I’ve checked so far:Bad tip: Tested all the tips, but nothing changed.Bad coax cable: Checked continuity, and it seems fine.Power supply issues: Possibly, but nothing obvious.According to the manual, a red light means it’s in protection mode. I couldn’t find any visible issues, and even the capacitors have good ESR. Should I consider checking the RF signal next?I’ve attached some photos of the internals—maybe someone with RF expertise can help me figure it out (main source seems to be classic 74hc04 + crystal based oscillator). And IRF130 as well - Haven't checked it yet... I’m not very experienced with RF circuits. 😅For context, I have a signal generator and an oscilloscope available.

author: kirill_maker
author_rank: Contributor
timestamp: November 25, 2024, 12:53:41 pm
content: And more photos due to max 8MB restriction

author: quadtech
author_rank: Regular Contributor
timestamp: November 25, 2024, 04:05:49 pm
content: From whatever I have read about this model, it is similar to the MX500, but lacks thesleep timer function (and probably the tip sense circuitry), so you should be able to use the MX500 schematic.This one uses L4960 (40V max) vs the LM2576 in the MX500.Apparently , Q1, Q2, Q4, C3 and C6, R2, R8, R9, R10 are possible failure points.

author: kirill_maker
author_rank: Contributor
timestamp: November 25, 2024, 05:11:59 pm
content: Ack, thanks! Will check

author: FIXITNOW2003
author_rank: Regular Contributor
timestamp: November 26, 2024, 07:39:44 am
content: some info here may helphttps://www.eevblog.com/forum/repair/metcal-stss-001-rfg-30-disassembly-and-measurements/msg5578273/#msg5578273

author: jonpaul
author_rank: Super Contributor
timestamp: November 26, 2024, 07:57:23 am
content: Usual chi com junk.buy genuine MetcalWe designed SP-200 500 kHz in 1990sUsed on epay ~$100j

author: kirill_maker
author_rank: Contributor
timestamp: November 27, 2024, 09:29:25 am
content: Ok:Checked all transistors - ok, but need to check Q4 (aka IRF130 in my variant) on curve tracer - just for case.Checked power resistors - ok.Checked caps - ok, but replaced with fresh one (just in case).To do:Check 74hc06 for signal generation.Re-checked cable - resistance with connected tip 12 Ohm, capacitance of disconnected cable with disconnected nozzle on 10KHz is ~200pF

author: kirill_maker
author_rank: Contributor
timestamp: November 27, 2024, 09:30:09 am
content: Wad? It's made in USA even with inch style screws...

author: macboy
author_rank: Super Contributor
timestamp: November 28, 2024, 09:53:26 pm
content: Maybe j forgot Metcal also makes 13MHz stations in addition to the later 500kHz ones he designed. Both types are excellent.In any case, yours appears to be a genuine metcal. I hope you can get it working, it will be worth the effort.The cable needs more than just continuity. It has an inductor and capacitor near the connector at the tip end (not station end). Some people have found that one or both of these can go bad, causing the handle/cable to not longer work. The best method of troubleshooting is to have a known good power supply to test the handle you have, and a known good handle to test your power supply. Otherwise you can't know which one is bad (or maybe both).

author: kirill_maker
author_rank: Contributor
timestamp: November 28, 2024, 10:05:35 pm
content: Unfortunately its first and only metcal that I have around. Is there way to examine cable with signal generator and fft analyzer? I dont have vna - yet , but maybe if i will crank up 13.56 mhz to cable i should see signal power drop ?