Thinking of buying a ZD985 desoldering station? Vacuum pump diaphragm fail. - Page 1
Forum section: electronics / repair

author: Lorenzo_1
author_rank: Regular Contributor
timestamp: February 25, 2019, 12:07:25 pm
content: Thought some might be interested in this pump failure as it seems the ZD985 is quite popular as a low-cost hobby option. Bought this one a couple of years ago - it's served well but not had a huge amount of use. Pump jammed in use and photos show the problem. The motor drives an eccentric cam attached to two rubber(?) diaphragms. The top of one diaphragm has torn off completely. Trying to source replacement diaphragms but not hopeful.Looking for replacement options. Supply to pump is 6V DC. Motor has markings for ELT-MOTOR.com and model ELT-555-35046. Closest I can find at ELT-linked site is an ELT-550SH-75020 which has specs of 1.04A at 3.6V nominal (operating range is 2.4-9.6V) and 6.75A at 6400rpm & max efficiency. The ELT-555SH listed with it needs 15-36V so doesn't fit the bill. The ZD985 motor might be custom-made. Will try and measure what the supply can deliver. I'm thinking the best option might be a different/better quality pump. Original spec is given as 230mm Hg (30kPa/307mB) vacuum but no details on flow rate.Has anyone found a good alternative? Would prefer one that will fit internally without needing an auxiliary supply. Plenty of options online but will need to pin down the spec better.

author: amyk
author_rank: Super Contributor
timestamp: February 25, 2019, 01:04:20 pm
content: If you search "aquarium pump diaphragm" you will find some awfully similar-looking parts.In any case, an aquarium air pump converted to vacuum might fit.

author: Muttley Snickers
author_rank: Unknown
timestamp: February 25, 2019, 02:28:41 pm
content: I remember somebody else having a similar problem but forget which thread it was in. Anyway, the manufacturers website moto declares"Quality Excellent Customers First"so send them an email message and ask if they stand by their products by providing spare parts.Otherwise perhaps you could contact Rhino Tools in Sydney and see if they have any spares available for these units, they are generally very good and most helpful. I've had a ZD-917 for a few years and with heavy usage it's still going great guns, touch wood.www.china-zhongdi.comhttps://rhinotools.com.au

author: Lorenzo_1
author_rank: Regular Contributor
timestamp: February 26, 2019, 10:01:29 am
content: Thanks for the suggestions. I'm hopeful Rhino Tools can help. The zhongdi link is useful as a fallback just in case. Looked at lots of possible substitute diaphragms but haven't yet found anything close.

author: Segasonicfan
author_rank: Newbie
timestamp: June 07, 2020, 10:58:01 pm
content: Quote from: Lorenzo_1 on February 26, 2019, 10:01:29 amThanks for the information here. Any update with what the manufacturer said or if you ever finish this repair? I have a similar problem and would love to know

author: Lorenzo_1
author_rank: Regular Contributor
timestamp: June 09, 2020, 05:00:17 am
content: Rhino Tools was able to supply a new pump. Easily fitted and working fine since though not getting a lot of use.

author: EJP
author_rank: Newbie
timestamp: July 07, 2020, 11:17:13 am
content: Rhino Tools no longer sell this unit, and never supplied the diaphragms. After a long search I will have a supply of ZD985 pump diaphragms in a few weeks. Please contact me off list if interested.EJP

author: EJP
author_rank: Newbie
timestamp: July 21, 2020, 12:44:30 am
content: I now have these pump diaphragms in stock. $A2.00 per pair including the zip tie plus postage plus GST. Contact me off list.EJP